Cook County Tax Assessment Search & Records

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Cook County, Illinois · PIN · Assessment · EAV · Tax Bill · Appeals

Search the PIN, Decode the Assessment, and Check the Tax Record

Use Cook County’s official property systems to search an assessment by address or 14-digit Property Index Number, verify market and assessed values, review property characteristics, check exemption history, compare prior assessments and see the tax record tied to the parcel.

The key is knowing which number actually matters. The Assessor determines value and exemptions, the Treasurer handles bills and payments, the Clerk helps with tax-rate and recorded-property functions, the Board of Review provides a second assessment appeal route, and CookViewer helps connect the PIN to maps and comparable properties.

Start the assessment search Understand the tax math Check appeal timing
Do not confuse assessed value with the amount of tax you owe. Cook County’s Assessor establishes assessment values, while the Treasurer bills and collects taxes. A property can have a correct assessed value and still have a tax bill that changes because of the state equalizer, exemptions, local tax rates or taxing-district levies.

Quick answer: use the Assessor for the assessment record

If you know the address, use the Cook County Assessor address search. If you already have the 14-digit PIN, use the PIN search because it is the cleanest way to open the exact property. For a combined view of tax history, exemptions, refunds, appeals and recorded-property links, use the Cook County Property Tax Portal after confirming the PIN.

1 Find the PIN Search by address or enter the full 14-digit parcel number.
2 Verify the parcel Match address, township, class and property characteristics.
3 Read the values Compare market value, assessed value, land and building amounts.
4 Finish the task Move to tax, exemption, appeal, GIS or deed records.

Cook County tax-assessment facts for 2026

Primary identifier 14-digit Property Index Number
Residential level Usually 10% of market value
Most commercial Usually 25% of market value
2025 state equalizer 3.0300
2026 reassessment South & west suburban cycle
1st installment April 1, 2026 — passed
2nd installment October 1, 2026
Assessor phone 312-443-7550
Treasurer phone 312-443-5100
Main Assessor office 118 N. Clark St., Room 320
Address-search quirk: in the Assessor’s Street Name field, enter only the street name. Do not type “Street,” “Avenue,” “Place,” “Lane,” “St.,” “Ave.” or similar suffixes. Start with the minimum information needed and narrow only if multiple results appear.
Search official Assessor records Open Property Tax Portal

Choose the record or tax question you need to solve

The same PIN connects several Cook County systems, but each office controls a different part of the property-tax process.

Cook County office routing

Assessment, tax bill, deed and appeal records come from different offices

A
ASSESSOR Value
Characteristics
Exemptions
First appeal
$
TREASURER Tax bill
Payment
Refund
Delinquency
C
CLERK Tax rates
Prior tax data
Maps
Recordings
B
BOARD OF REVIEW Second appeal
Decisions
Township filing
Evidence
G
COOKVIEWER GIS map
PIN lookup
Comparables
History links
Which Cook County office controls the answer?
Your question
Use this office/tool
What it provides
Important limit
What is my property’s assessed value?
Cook County Assessor
Market value, assessed value, class, property characteristics and exemption history.
The Assessor does not collect your tax payment.
How much property tax do I owe?
Cook County Treasurer
Current bill, payment status, delinquency, refunds and payment options.
The Treasurer does not determine market value.
What is the local tax rate?
Cook County Clerk / tax records
Tax-rate and prior-year property-tax functions.
Tax rate is not the same as assessment level.
Can I challenge the Assessor?
Assessor, then Board of Review
Township-specific assessment appeal opportunities.
Each filing window has its own deadline.
Where can I compare nearby parcels?
CookViewer
Map, PIN, values, characteristics and comparable-property tools.
Mapped boundaries are not a professional survey.
Where is the deed or mortgage?
County Clerk Recordings
Recorded deeds, mortgages, liens and other instruments.
Assessment ownership display is not a title opinion.
Best workflow: find the 14-digit PIN once, save it, and use that same identifier across the Assessor, Treasurer, Property Tax Portal, CookViewer and recorded-property research.
Portal quirks most guides miss

Use Advanced Search when one exact parcel search is not enough

Cook County’s Assessor uses its own web property-search system rather than a standard Beacon or qPublic installation. The Advanced Search tool is especially useful for appeal research, partial PINs, address ranges and finding records connected to an existing appeal.

First 10 PIN digits

Useful when you know the base parcel but not the final unit or subparcel digits.

Address range

Search a range of house or unit numbers on the same street.

Appeal search

Search by applicant, attorney or appeal-number combination.

PIN range

The advanced tool accepts partial PIN searches using eight or more digits.

Comparable-property shortcut: combine a township, property class and address/PIN range rather than searching random nearby houses. Comparable assessment evidence is stronger when the properties are genuinely similar.
Open Assessor Advanced Search
No-result troubleshooting

No Cook County assessment result? Diagnose the search first

Full street name failed Remove Street, Avenue, Road, Place, Lane, Boulevard and their abbreviations.
Direction may be wrong Search without N, S, E or W first; add it only when needed to distinguish matches.
Condo building has many results Add the unit number or switch to the exact 14-digit PIN.
You only have part of the PIN Try the Advanced Search or CookViewer using the available PIN digits.
Parcel was recently divided Search the previous PIN and inspect current/nearby parcels in CookViewer.
Owner-name search is not working The primary Assessor lookup is built around address and PIN. Use deed/recording research for grantor or grantee name searches.
Address points near several parcels In CookViewer, an address locator can return parcels close to the entered location. Select the exact PIN.
Property record looks old Compare assessment year, tax year and payable year before assuming the database is wrong.
Assessor call script “I am trying to identify the correct assessment record for [property address]. I have [full or partial PIN], and the property appears to be in [township]. The search is returning [no result / several condo PINs / an older parcel]. Can you help me identify the current PIN and assessment record?”
Call Assessor: 312-443-7550
Assessment record decoder

Read the property record without confusing value, EAV and tax

Cook County assessment fields explained
Field
What it means
What to verify
PIN
Property Index Number identifying the parcel.
Use the same PIN on tax, GIS and appeal systems.
Township
Assessment district controlling reassessment and appeal timing.
Check the live township appeal calendar.
Property Class
Classification assigned based on use and characteristics.
Classification affects assessment level and comparable selection.
Estimated Market Value
Assessor’s opinion of the property’s fair market value.
Compare against market evidence before appealing.
Assessed Value
Market value multiplied by the assessment level for the property’s class.
Residential is generally 10%; most commercial is generally 25%.
Land Assessed Value
Assessment attributed to land.
Parcel size, use and classification.
Building Assessed Value
Assessment attributed to improvements.
Square footage, age, class, use and physical characteristics.
Equalized Assessed Value
Assessed value after application of the state equalization factor.
Subtract qualifying exemptions before applying the local tax rate.
Tax Code
Code representing the combination of taxing districts serving the parcel.
Use the actual second-installment bill for final tax-rate information.
Exemption History
History of tax-saving exemptions associated with the property.
Investigate missing Homeowner, Senior or other exemptions quickly.
Appeal History
Assessment appeal filings and results where displayed.
Save docket, appeal or complaint numbers.
Certificate of Error
Post-assessment correction route for certain valuation or exemption issues.
Use the correct office for status and any resulting refund.

Check property characteristics before arguing about value

Building square footage
Property class
Number of units
Building age
Garage information
Basement / attic information
Land square footage
Current property use
Appeal-quality tip: a documented factual error—such as incorrect square footage or property class—is usually more useful than simply saying the tax bill feels too high.
Cook County assessment math

Residential 10%, most commercial 25%—then the state equalizer applies

10% is the residential assessment level, not the tax rate

A typical Class 2 residential property is assessed at 10% of estimated fair market value. Most commercial property is assessed at 25%. Multifamily apartment property can fall under a 10% level depending on classification.

For Tax Year 2025, payable in 2026, Illinois announced a final Cook County equalization factor of 3.0300. That factor converts assessed value to Equalized Assessed Value before applicable exemptions are deducted.

MARKET VALUE Assessor estimate 10% OR 25% Assessment level × 3.0300 2025 equalizer − EXEMPTIONS Adjusted EAV × TAX RATE Tax calculation
Residential example

$400,000 estimated market value

× 10% assessment level

= $40,000 assessed value

× 3.0300 equalizer

= $121,200 EAV before exemptions

Commercial example

$1,000,000 estimated market value

× 25% assessment level

= $250,000 assessed value

× 3.0300 equalizer

= $757,500 EAV before exemptions

Do not use these examples as a tax quote. The actual tax bill depends on the parcel’s classification, exemptions, local tax rate, taxing districts, special circumstances and final certified values.
Read official assessment math
Current 2026 tax status

Tax Year 2025 bills are payable in 2026

First installment April 1, 2026

The on-time due date has passed.

Second installment October 1, 2026

Current published due date.

Late interest 0.75% per month

State-law late interest shown by the Treasurer.

Why the two installments look different

First installment

Cook County states that the first installment is generally 55% of the prior year’s total property tax. Current-year exemptions are not reconciled on this installment.

VS
Second installment

The second bill reflects the completed current-year tax calculation, including applicable exemptions and the final tax-rate information.

Check the bill before paying

Open Your Property Tax Overview Search using the exact 14-digit PIN or property address.
Confirm the property image and location Make sure the payment belongs to the correct parcel.
Check Payment Status Verify whether an escrow company, lender or another payer already submitted payment.
Review the current amount If a payment is already late, do not rely on the amount printed for the original due date.
Choose an approved payment method Bank-account ACH payment is published as fee-free; card payments carry third-party processing charges.
Save the receipt Keep the PIN, tax year, installment, payment amount and confirmation.
Treasurer call script “I am calling about PIN [14-digit PIN] at [address]. Can you confirm the current Tax Year 2025 balance, whether any payment has posted, whether late interest applies, and the amount required for the correct installment?”
Open Treasurer tax search Call Treasurer: 312-443-5100
Missing tax savings

Check exemption history before assuming the second bill is correct

Open the Assessor property details and review the Exemption History and Status section. The normal Tax Year 2025 exemption filing period has ended; applications received after May 15, 2026 are processed through the Certificate of Error route.

Major Cook County homeowner exemptions
Program
Who it generally helps
Current 2026 detail
Renewal
Homeowner
Qualifying owner-occupants using the home as their principal residence.
Reduces EAV by $10,000.
Automatic after approval while eligibility continues.
Senior
Qualifying homeowners age 65 or older.
Reduces EAV by $8,000.
Automatic after approval.
Senior Freeze
Qualifying senior homeowners meeting the income test.
Current Tax Year 2025 guidance uses household income of $65,000 or less for calendar year 2024.
Must be filed annually.
Persons with Disabilities
Qualifying homeowners with disabilities.
$2,000 EAV reduction.
Current guidance says automatic renewal applies under new legislation.
Veterans with Disabilities
Qualifying veterans with VA-certified service-connected disability.
Benefit depends on disability level and other eligibility rules.
Current guidance requires annual filing.

Missed May 15, 2026?

Open Exemption History first Confirm that the exemption is actually missing.
Identify the correct tax year Do not file for the wrong year because the bill is payable in a later calendar year.
Use the current Certificate of Error path The Assessor now routes late Tax Year 2025 exemption applications through that process.
Prepare program-specific proof Ownership, occupancy, age, income, disability or veteran documents vary by exemption.
Save the application confirmation Check status instead of filing a duplicate application.
Senior Freeze does not freeze the tax bill. It freezes qualifying Equalized Assessed Value. The local tax rate can still change, so the final property-tax bill can rise or fall.
Check official exemption programs
Township-specific 2026 appeals

Appeal the assessment—not simply the size of the tax bill

Current calendar snapshot reviewed August 20, 2026: the Assessor’s calendar lists West Chicago open through August 21, Lyons through September 3 and Northfield through September 4. Township statuses change throughout the season, so always use the live calendar before filing.
2026 reassessment cycle: south and west suburban Cook County properties are undergoing triennial reassessment in 2026. North-suburban and City of Chicago properties are generally not in their scheduled triennial reassessment year, although individual properties can still change because of permits, divisions or other circumstances—and owners can still appeal when their township opens.
01
VERIFY Check PIN, township, class and property characteristics.
02
CALENDAR Confirm the township opening and last file date.
03
EVIDENCE Build market, uniformity or factual-error support.
04
FILE Submit through the Assessor appeal system.
05
SECOND REVIEW Use the Board of Review when appropriate.

When an appeal may make sense

Overvaluation Recent sale, appraisal or market evidence supports a lower market value.
Uniformity Similar properties are assessed lower after adjusting for meaningful differences.
Incorrect square footage The record materially overstates or understates building size.
Wrong classification The parcel is classified in a way that does not match actual use or characteristics.
Damage or demolition Flood, fire, demolition or another condition materially affected value.
Commercial evidence Income, vacancy, rent, operating expense or capitalization evidence supports a different value.

Assessor appeal vs. Board of Review

Assessor appeal

This is the first assessment-review opportunity. Filing periods are township specific and are commonly about 30 days after the reassessment notice.

THEN
Board of Review

Provides a separate second-level assessment appeal. The 2026 appeal season is open, filing is free, and township filing periods still control.

Do not compare random low-assessment properties. Stronger comparables generally share the same or similar property class, neighborhood, size, age, use and relevant market characteristics.
Check live Assessor calendar Open Board of Review
2026 CookViewer workflow

Use CookViewer when you need maps, partial PINs or comparable properties

CookViewer’s May 28, 2026 release provides property searching, assessed values, building characteristics, comparable-property tools, map exports and links to other Cook County property resources.

CookViewer accepts more search formats than the Assessor’s basic form

10-digit PIN

Useful when you only have the base PIN.

14-digit PIN

Best for an exact parcel or condo unit.

Dashes accepted

Example: XX-XX-XXX-XXX-XXXX.

Address / intersection

Useful when you do not yet know the PIN.

Enter the most specific identifier available Use the 14-digit PIN when possible.
Open the exact Property Result The map automatically zooms to the selected parcel.
Review Assessed Value Check current land, building and total assessment fields.
Open Property Comparison Compare by class, neighborhood, square footage and age.
Export useful records CookViewer can export search results to CSV or Excel.
Use historical parcel layers carefully Archive layers can show changing parcel boundaries over time.
Condo warning: selecting a high-rise or multi-unit building can return multiple stacked parcel PINs. Choose the exact unit PIN rather than assuming the first result is the correct assessment.
Boundary warning: CookViewer is a research tool. Do not use a mapped parcel outline as a substitute for a deed, recorded plat or professional boundary survey.
Open CookViewer
Historical tax and ownership records

Use the Property Tax Portal for tax history—and the Clerk for recorded ownership documents

Which record answers which question?
Record
Best source
What you can learn
Important limit
Assessment history
Assessor / CookViewer
Prior assessed values and property characteristics.
Assessment history is not payment history.
Original tax billed history
Cook County Property Tax Portal
Five-year history of original tax amounts billed.
Current payment status should be checked with the Treasurer.
Longer tax history
Treasurer property overview
Cook County Treasurer promotes access to property-tax history extending back many years.
Use the live account for current balances.
Exemption history
Assessor
Which exemption programs were applied by tax year.
A missing exemption may require a Certificate of Error filing.
Appeal history
Assessor / Board of Review
Appeal filings, docket information and prior decisions where available.
Past approval does not automatically guarantee a new reduction.
Deed / mortgage / lien
Cook County Clerk Recordings
Recorded ownership and financing documents.
A public search is not a professional title examination.

Deed-search micro workflow

Find the PIN first Use the Assessor or CookViewer so you are not relying only on an owner’s name.
Open County Clerk Recordings Use the current Clerk recording system for land-record research.
Search the parcel and names Use grantor/grantee information where needed.
Check document type and recording date Distinguish a deed from mortgage, release, lien or easement.
Order certification only if required Research copies and certified legal-use copies are not always the same service.
Ownership safety: the Cook County Clerk also provides a free Property Fraud Alert service that can notify registrants when documents associated with registered property information are recorded.
Open Property Tax Portal Open Cook County Clerk
Related CountyAuditors.org guide

Need the broader Cook County property-search workflow?

Cook County Property Search: Assessor, Tax Records & GIS

Use the broader property-search guide when your main goal is to find a parcel, use CookViewer, research GIS, check deeds or troubleshoot a general PIN/address lookup rather than focus specifically on tax assessment records and calculations.

Open the Cook County property-search guide

Contact and visit planning

Cook County assessment, tax and appeal contacts

Who to call before visiting 118 North Clark Street
Office
Use it for
Phone
Main office
Cook County Assessor
Assessment values, property characteristics, exemptions and Assessor appeals.
312-443-7550
118 N. Clark St., Room 320, Chicago, IL 60602
Cook County Treasurer
Tax bill, payments, delinquency, refunds and payment status.
312-443-5100
118 N. Clark St., Room 112, Chicago, IL 60602
Cook County Clerk Recordings
Deeds, mortgages, liens and recorded real-estate documents.
312-603-5050
118 N. Clark St., Room 120, Chicago, IL 60602
Cook County Board of Review
Second-level property assessment appeals.
312-603-5542
118 N. Clark St., Room 601, Chicago, IL 60602

Have this ready before calling

14-digit PIN
Property address and unit
Township
Assessment or tax year
Property class
Appeal / complaint number
Tax installment
Short description of the problem
Universal Cook County call script “I am calling about PIN [PIN] at [address]. I need help with [assessment / exemption / tax bill / appeal / deed]. The online record currently shows [brief fact]. Can you confirm which record controls this issue and what I should do next?”
Before relying on the record

Assessment records are powerful—but they are not complete real-estate due diligence

Assessment records are useful for
  • Finding market and assessed values
  • Checking property class
  • Reviewing building characteristics
  • Checking exemption history
  • Finding appeal history
  • Preparing comparable research
Use stronger verification for
  • Legal ownership and title
  • Recorded liens and easements
  • Exact boundary location
  • Current zoning approval
  • Building-code compliance
  • Current payoff or tax-sale status
Do not use Assessor ownership or GIS data as a substitute for title work or a survey. Tax-assessment, recording, zoning, tax-payment and boundary records answer different legal and financial questions.
10 practical answers

Cook County tax assessment search FAQs

How do I search a Cook County property tax assessment?

Use the Cook County Assessor property search. Search by property address or the full 14-digit Property Index Number. After opening the record, verify the PIN, township and property class before relying on the assessment values.

What is a Cook County Property Index Number?

The PIN is the parcel identifier used throughout Cook County property systems. The Assessor commonly uses the full 14-digit PIN, while CookViewer can also search by a 10-digit PIN, a 14-digit PIN or a dashed PIN.

Why is my address not showing in the Cook County Assessor search?

Enter only the street name in the Street Name field. Remove suffixes such as Street, Avenue, Place, Road or their abbreviations. Also try removing the directional and adding a condo unit only when necessary.

What percentage of market value is assessed in Cook County?

Residential property is generally assessed at 10 percent of estimated market value. Most commercial property is generally assessed at 25 percent. Classification and incentive rules can create exceptions.

What is the 2025 Cook County equalization factor?

The Illinois Department of Revenue announced a final 2025 Cook County property-tax equalization factor of 3.0300. The factor is applied to assessed value to help calculate Equalized Assessed Value.

When are Cook County property taxes due in 2026?

The Tax Year 2025 First Installment was due April 1, 2026. The Treasurer’s current payment information lists the Tax Year 2025 Second Installment due date as October 1, 2026.

How do I check my Cook County property-tax exemptions?

Open the Assessor property record and review Exemption History and Status. Applications received after May 15, 2026 for Tax Year 2025 are processed through the Certificate of Error route under the current Assessor guidance.

How do I appeal a Cook County property assessment?

Find the property’s township, check the Assessor’s current Assessment and Appeal Calendar and file during that township’s open period. A separate appeal opportunity may also be available through the Cook County Board of Review.

Where can I see Cook County property-tax history?

The Cook County Property Tax Portal provides a five-year history of original amounts billed for a PIN and links to current tax-payment information. The Treasurer’s property overview provides additional tax and payment information.

Where do I find Cook County deeds, mortgages and liens?

Recorded real-estate documents are handled through the Cook County Clerk Recordings function. Find the correct PIN first, then use the recorded-document system for deed, mortgage, lien, release and related document research.

Information reviewed August 20, 2026: Assessor search fields and Advanced Search options, 2026 reassessment and appeal calendar, residential and commercial assessment levels, the final 2025 Cook County equalization factor, current exemptions and Certificate of Error filing status, Tax Year 2025 installment dates, late-interest guidance, CookViewer functionality, Board of Review filing information and primary Cook County property-office contacts were checked against current official sources.
Independent Guide — Legal and Accuracy Disclaimer: CountyAuditors.org is an independent informational directory and is not the Cook County Assessor, Cook County Treasurer, Cook County Clerk, Cook County Board of Review, Cook County GIS Department, Illinois Department of Revenue or any other government office. Assessment records are provided for research and taxpayer guidance. Confirm live tax balances, filing deadlines, appeal windows, exemption eligibility, tax rates, recorded instruments, title matters and legal property boundaries directly with the responsible public office or qualified professional before making a legal or financial decision.
Ohio Auditor Tools · Tax Year 2026

10 Ohio Property Tax Calculators & Auditor Tools

Built specifically for Ohio's 35% assessment ratio, current DTE forms, and 2026 Homestead, Owner-Occupancy, CAUV, Conveyance Fee, and Board of Revision rules. Every number reflects verified Ohio Department of Taxation amounts.

Homestead: $29,000 Enhanced Vet: $58,000 OAGI limit: $41,000 Assessment: 35% of market BOR filing: Free · DTE 1

Annual Tax Bill Estimator

OHIO

Applies Ohio's 35% assessment ratio plus your county's effective millage tier — the actual math your auditor uses.

Pick a county tier and enter your market value.

Homestead Reduction Calculator

DTE 105A

2026 Ohio Homestead: $29,000 general or $58,000 enhanced (100% disabled vet, KIA spouse). OAGI under $41,000 required for non-veteran applicants.

Pick your situation and enter your home value.

Owner-Occupancy & Non-Business Credits

DTE 105C

Every Ohio owner-occupied home qualifies for the 2.5% Owner-Occupancy Credit plus the automatic 10% Non-Business Credit. Most owners don't realize these stack.

Enter your annual tax to see both credit amounts.

Conveyance Fee Calculator

ORC 322

When you sell or transfer Ohio property, the auditor collects $1 state + up to $3 county per $1,000, plus $0.50 per parcel. Counties choose their rate.

Enter sale price and pick your county rate.

CAUV Agricultural Savings

DTE 109

Ohio's Current Agricultural Use Value cuts taxable value dramatically for farmland (10+ acres, or smaller with $2,500+ annual gross income).

Enter both market and CAUV values to see savings.

Mill Rate Converter

Ohio tax rates appear three ways on auditor sites: mills, percent, or dollars per $1,000. Convert between them instantly.

Enter a rate to see all three forms.

Parcel Number Cleaner

Ohio's 88 counties each format parcels differently — Franklin uses 010-123456-00, Cuyahoga uses 001-23-456, Hamilton uses 100-0001-0001-00. Auto-detects.

Paste any Ohio county parcel to format it.

35% Ratio Sanity Check

Ohio law sets taxable value at 35% of market value. If yours is significantly higher, you're a strong BOR appeal candidate.

Enter both values to compare against Ohio's 35% target.

BOR Appeal Savings

DTE 1

A successful Board of Revision complaint typically cuts your value 10–20%. Filing is free and stays in effect until the next reappraisal.

Enter your tax bill and reduction estimate.

BOR Deadline Countdown

MAR 31

Ohio's statutory Board of Revision filing deadline is March 31 for the prior tax year. Miss it and you wait until next year — no extensions.

Set your deadline to start the countdown.

Verify with the official Ohio source

These calculators use the verified 2026 Ohio Department of Taxation amounts and statutory rules. For your exact bill, exemption status, and county-specific deadlines, always confirm with your county auditor and the Ohio Revised Code:

Ohio Dept. of Taxation — Real Property DTE Forms (105A, 105C, 1, 109) ORC 5715 — Board of Revision ORC 5713 — Taxable Real Property ORC 322.02 — Conveyance Fee ORC 319.54(F)(3) — State Fee ORC 5713.30 — CAUV tax.ohio.gov — Main Portal

Estimates use Ohio's 35% statutory assessment ratio and effective tax rate tiers averaged across major Ohio counties. Your actual bill depends on local school levies, voted millage, inside vs. outside millage splits, House Bill 920 reduction factors (HB 920), and special assessments. The 2026 Homestead general amount ($29,000) and enhanced amount ($58,000) reflect HB 187 inflation indexing — your county auditor's office may show slightly different transitional figures. Nothing here is legal or tax advice. CountyAuditors.org is an independent informational directory, not affiliated with any county government.

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