Appraisal Adjustment Calculator

Enter subject GLA, comp GLA, and rate to see the adjustment.

Subject vs. Comp GLA

When a comparable sale has more or less GLA than the subject property, appraisers make a dollar adjustment to account for the difference. See our guide on comparable square footage adjustments for a deeper look.

The adjustment rate

The $/sqft rate is derived from paired sales analysis in your market. It is not the price per sqft of the home: it reflects only the contribution of GLA to value.

ANSI Z765 compliance

GLA must be measured using ANSI Z765 standards: above grade, finished, heated/cooled living space only. Basements and garages are excluded.

What is a GLA adjustment in an appraisal?

A GLA adjustment accounts for the difference in gross living area between the subject property and a comparable sale. When a comp has more or fewer square feet than the subject, the appraiser adds or subtracts a dollar amount per sqft to bring the comp's sale price in line with the subject.

How do I determine the right $/sqft adjustment rate?

The rate comes from paired sales analysis. Finding two sales that are identical except for GLA, then calculating the price difference per sqft. Typical ranges are $25–$75/sqft, but it varies by market, price tier, and property type. Avoid using the home's overall price per sqft as the adjustment rate.

What is the difference between GLA and total square footage?

GLA (Gross Living Area) is only the above-grade, finished, heated and cooled living space. Measured per ANSI Z765-2021. Finished basements, garages, and unheated spaces are excluded. Total square footage is a loosely defined term that may include any or all of these areas.

Do I make a positive or negative adjustment to the comp?

If the subject has more GLA than the comp, the comp underrepresents value. Make a positive adjustment. If the subject has less GLA, make a negative adjustment. This calculator shows the direction automatically based on your inputs.