Pennsylvania Common Level Ratio (CLR): Assessed Value vs Market Value

Last updated May 18, 2026

·Independent Pennsylvania tax education

Pennsylvania's property tax system is unusual: most counties assess property at values frozen to a base year that may be decades old. The Common Level Ratio, published annually by the State Tax Equalization Board, is the bridge between that frozen assessed value and current market value. Understanding the CLR is the single most important concept in most PA assessment appeals outside Philadelphia.

Key takeaways

The Common Level Ratio (CLR) is the average ratio of assessed value to fair market value in a Pennsylvania county.
The State Tax Equalization Board (STEB) calculates and publishes the CLR every year for all 67 counties.
Most PA counties use a frozen base-year assessed value. The CLR is what bridges that frozen value to current market.
Implied market value = assessed value × (100 / CLR). If your assessment implies a market value higher than reality, you may have an appeal.
Allegheny County's shift from a higher predetermined ratio to the STEB-published CLR triggered a wave of appeals — the same math now drives appeals in other counties.

What the Common Level Ratio (CLR) is

The Common Level Ratio (CLR) is the State Tax Equalization Board's measurement of how Pennsylvania counties' assessed values compare to actual sale prices over a defined sales study window. It's expressed as a percentage. A CLR of 50.0 means the typical assessed value in that county is approximately half of fair market value; a CLR of 100.0 would mean assessed value tracks market value one-for-one.

Each of Pennsylvania's 67 counties has its own CLR, because each county reassesses on its own schedule (or doesn't). Counties that did a recent reassessment have CLRs near 100; counties whose last reassessment was in the 1970s often have CLRs in the single digits.

How STEB calculates the CLR

STEB studies arm's-length sales in each county during a defined sales study period, compares each sale price to the property's assessed value, and computes the median ratio. That median is the official CLR for the tax year that follows. The figure is published once per year and is the number courts and county boards use.

Base year vs current year — PA's unusual system

Most PA counties assign every property a base-year value: the assessed value reflects what the assessor thought the property was worth in a specific past year. The county does not refresh that base-year value automatically. In fact most PA counties have not done a county-wide reassessment in decades.

Inflation in real estate values is real, though. The CLR is the legislative answer to the gap between frozen base-year assessments and rising market reality. Cap the new tax burden at a known ratio; let appeals correct individual outliers.

Finding your county's current CLR

STEB publishes a CLR table for all 67 counties annually. The current and historical tables are available through the Department of Community and Economic Development. The published ratio applies to assessment appeals decided during the relevant tax year.

Worked example: implied market value

Concrete example. Suppose your county's CLR is 60.0 and your property's assessed value is $120,000.

Implied market value = $120,000 × (100 ÷ 60) = $200,000.
If three nearby, similar homes recently sold for $170,000, $175,000, and $180,000, your appeal evidence supports a value closer to $175,000.
$175,000 × (60 ÷ 100) = $105,000 — the assessed value you would argue for.
At a combined millage of, say, 80 mills, that reduction saves roughly $1,200 per year.

The savings compound — successful appeals usually carry forward until the next county-wide reassessment.

Why CLR is the linchpin of most PA appeals

For PA counties with old base years, every assessment appeal comes down to one math problem: does the assessed value imply a market value higher than the actual market value? The CLR turns assessed value into implied market value. Comparable sales prove the actual market value. The gap is the appeal.

The Allegheny CLR shift and ripple effect

Allegheny County had been applying a Predetermined Ratio higher than the STEB CLR for years. In 2022, Pennsylvania courts found that taxpayers were entitled to insist on the STEB-published CLR when the predetermined ratio diverged materially. The CLR for Allegheny dropped sharply, dramatically raising the implied market value the same assessed value represents, and producing a wave of appeals.

The decision is most relevant for Allegheny but has informed appeals in other counties that publish their own ratios. The underlying principle — the STEB CLR is the legally sanctioned ratio — applies statewide.

For the Allegheny-specific procedure, see our Allegheny County appeal procedure guide.

When the CLR helps you, and when it doesn't

The CLR helps the owner when the implied market value is higher than the property's actual market value. That happens when:

The county hasn't reassessed in years and the CLR is below 100.
Your specific property has features the model overweighted.
Local market conditions have softened relative to the broader county.

The CLR works against the owner when:

The implied market value is lower than what the property would actually sell for today.
You just bought the property at a price well above the implied value.
A taxing authority is positioned to file a reverse appeal.

Best practices

Pull the current STEB-published CLR for your county at the start of every appeal year — it changes annually.
Use the CLR to compute your implied market value, then compare to comparable sales. The gap (if any) is your case.
Confirm your county's base year. The older the base year, the more out-of-sync the assessment usually is, and the more impact the CLR has.
If your county uses a Predetermined Ratio that diverges materially from the STEB CLR, cite the published CLR and request the math the court would use.
When you sell or buy in Pennsylvania, model the implied-market-value math into the deal — a sale above implied value invites a reverse appeal.

Common mistakes

Confusing the assessed value with the market value. They are different numbers connected by the CLR.
Using last year's CLR. STEB publishes annually — always confirm the current figure.
Ignoring the CLR in Philadelphia. AVI assessments use a different framework.
Filing a CLR-only argument without comparable sales evidence to support the alternative market value.
Assuming the CLR works equally well in every county. Counties that recently reassessed have CLRs close to 100, leaving little room.

Official Pennsylvania sources

PA State Tax Equalization Board (STEB)
Publishes the annual Common Level Ratio (CLR) for every Pennsylvania county.
PA County Assessors — directory by county
Find your county assessor for property tax appeals.
Pennsylvania Bar Association — attorney lookup
Find or verify a Pennsylvania attorney.

Frequently asked questions

What is the Common Level Ratio?

The Common Level Ratio (CLR) is the State Tax Equalization Board's measurement of how Pennsylvania counties' assessed values compare to actual sale prices. It's published annually as a percentage — for example, a CLR of 50.0 means the typical assessed value in that county is half of fair market value.

Who publishes the CLR?

The State Tax Equalization Board (STEB), within the Department of Community and Economic Development. STEB publishes a fresh table every year. The number is the official, court-respected ratio for that tax year.

How do I use the CLR to check my own assessment?

Divide your assessed value by the CLR / 100 to get the implied market value. If a similar home recently sold for less than that, your appeal evidence may be enough to win a reduction.

Does the CLR apply in Philadelphia?

Philadelphia uses the Actual Value Initiative, where assessed value is supposed to equal current market value directly. The CLR is much less relevant in Philadelphia than elsewhere in Pennsylvania. The CLR is most consequential in counties with long-frozen base years — Allegheny is the most prominent example.

Can the CLR ever hurt me in an appeal?

Yes. If your assessed value implies a market value lower than what your property is actually worth, the math cuts against you — and the taxing authority could file a reverse appeal. The CLR is a tool, not a one-way ratchet.

Next read

Comparable Sales Methodology

CLR turns assessed value into an implied market value. Comparable sales prove what the real market value actually is.

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Explanation

PA's base-year / CLR system is unusual and is the single most important concept in most PA assessment appeals. Strong worked-example structure with high local relevance.

Suggested improvements

Add expert review from a PA-licensed appraiser or property tax attorney.
Add the current STEB-published CLR table for all 67 counties.
Add a downloadable implied-market-value calculator.

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