Why Appraisers Adopted ANSI Home Measurement Standards
October 29, 2022
Why Appraisers Adopted ANSI Home Measurement Standards
By Joseph T Ellington Jr – Licensed Residential Appraiser, Capital Valuations. Updated September 2026.
This article originally discussed the adoption of ANSI Z765-2021 for Fannie Mae appraisal assignments. The core question remains: why can a freshly measured appraisal show a different square-footage figure from an older listing or tax record? The standard supplies a consistent method for measuring and reporting area. It does not guarantee every public record will match, and it does not mean every private assignment or property type uses the same lender rule.
What changed for applicable lender reports?
Fannie Mae’s current Selling Guide sets out above- and below-grade area and ANSI requirements for covered assignments and identifies exceptions. An appraiser documents dimensions and reports categories according to those rules, rather than automatically copying a tax-card figure. The more detailed companion article, our ANSI Z765-2021 appraisal guide, explains how the standard applies today.
Why numbers from tax and MLS records differ
A tax-card figure may be outdated or use a different reporting convention. An MLS listing may reproduce builder, owner or assessor data without an independent measurement. An appraisal sketch may reflect a measured dwelling and a specific report method, including separate categories for above- and below-grade finished space. Compare the underlying dimensions and dates before calling one figure an error.
A comparison to review before listing
| Source | Possible reason for a difference |
|---|---|
| Tax record | Older property data, an addition not reflected, or a different convention |
| MLS listing | Builder, owner or assessor figure supplied without new measurement |
| Appraisal sketch | Measured area and stated reporting method with separate area categories |
What owners and agents should do
- Ask what the figure includes, who measured it, and when.
- Keep plans and permits, but compare them with the actual finished property.
- If a listing conflicts with a new sketch, verify dimensions and area definitions before revising marketing material.
- Do not turn a measurement difference into an automatic dollar adjustment; market evidence controls value analysis. See our area-adjustment guide.
Private appraisal questions
This 2022-era adoption topic is retained as a historical explanation, while the companion guide addresses current reporting rules. For a private residential appraisal in Hampton Roads, contact Capital Valuations with the property and intended use.
