Can I use a floor plan to calculate GLA on a split-level home?

Yes, if you have separate floor plans for each level. Upload each floor plan to a tool like PlanSnapper, set scale, trace each level's exterior footprint, and sum only the above-grade levels. The challenge is correctly identifying which levels are above grade, which requires knowing how the home sits on the lot and where finished grade meets each exterior wall.

How do I use a floor plan to measure a split-level home?

Upload each level's floor plan to PlanSnapper separately. Trace the exterior perimeter of each level. Confirm which levels are above grade by checking exterior ground contact. Set scale using a known dimension and sum the above-grade finished areas for total GLA. Keep below-grade levels separate.

Do different split-level configurations have different GLA rules?

Yes. A standard split-level with a lower level half below grade treats that lower level as below-grade area. A split-entry or bi-level where the lower level is fully above grade on the walk-out side may qualify as above-grade. Each level must be evaluated against exterior ground level independently rather than by its position in the stair sequence.

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Measurement Guide

Part of: How to Measure Square Footage: The Complete Guide

How to Measure Square Footage of a Split-Level Home

Split-level and split-entry homes are among the most error-prone properties to measure for GLA. The grade question alone creates disagreement among appraisers. Here is how to work through it correctly.

What Makes Split-Levels Difficult

In a conventional two-story home, every level is clearly above grade. In a split-level, one or more levels sit partially below the surrounding grade. Whether a given level counts as above-grade or below-grade determines whether its square footage goes into GLA or into the basement section of the appraisal form. Get it wrong and you are either overstating or understating the GLA of the subject and potentially your comparables.

Split-entry homes (also called raised ranches) typically have an entry at grade level with living space a half-flight up and a lower level a half-flight down. Split-level homes may have three or more staggered levels. Each level must be evaluated independently.

The ANSI Z765 Grade Rule

ANSI Z765 defines a level as above-grade if the majority of its finished area is above the average grade of the surrounding earth. In practice, appraisers apply a common-sense test: if you walked around the exterior of the home and looked at a given level, is more of the exterior wall above the ground than below it?

A level where more than 50 percent of the perimeter exterior wall is above grade is generally treated as above-grade for GLA purposes. A level where more than 50 percent of the exterior wall is below grade is treated as below-grade, regardless of how finished it is.

The gray area is a level that is exactly half above and half below, or where grade varies significantly around the perimeter. In those cases, document your reasoning in the appraisal report. Lenders and reviewers can accept a judgment call when it is explained; they push back on unexplained decisions.

Quick reference: What counts as GLA by level type

Level	Grade status	Counts as GLA?	Where it goes in the report
Upper living level	Above grade (all sides above ground)	✅ Yes	GLA — add to total
Mid entry level (split-entry)	Above grade (half-flight up)	✅ Yes	GLA — add to total
Lower level, mostly exposed	Above grade (>50% perimeter above grade)	✅ Yes	GLA — add to total
Lower level, mostly buried	Below grade (<50% perimeter above grade)	❌ No	Below-grade finished area — separate line
Unfinished lower level	Below grade	❌ No	Noted in improvements, not in GLA or BGFA
Garage level	Any	❌ No	Garage, not GLA regardless of grade

Level-by-Level Measurement Approach

The cleanest way to handle a split-level is to measure each level as a separate unit, determine whether each level is above or below grade, and report accordingly. Here is a practical sequence:

Walk the exterior and note grade height at each corner of the building for every level.
For each level, measure the exterior dimensions as you would for a standard floor.
Determine above-grade vs. below-grade status based on the majority-of-perimeter rule.
Add above-grade finished levels to GLA. Report below-grade finished area separately.
Note the level count and any non-standard configuration in the improvement description.

Common Errors on Split-Level Appraisals

Treating all levels as above-grade. In a split-entry home, the lower level is almost always below grade. Including it in GLA inflates the subject and creates comp matching problems unless the comparables are handled the same way.

Reporting total finished area as GLA. A split-level with 1,400 sq ft of above-grade space and 700 sq ft of finished below-grade space has a GLA of 1,400, not 2,100. Reporting 2,100 as GLA misrepresents the property on a UAD form.

Using inconsistent treatment across comps. If you exclude the lower level from GLA on the subject but a comparable's MLS record included its lower level in the stated square footage, you need to adjust. Consistency across subject and comps matters more than any single convention.

Not noting the split-level configuration. Lenders reviewing the report need to understand why the GLA seems low relative to the total finished area. A brief note in the improvements section explaining the level configuration prevents unnecessary review requests.

Using Floor Plans to Document Split-Levels

A floor plan measurement tool that supports multiple polygons lets you draw each level separately, label each one, and get individual square footage per level. That output documents your measurement process clearly: level 1 above-grade at X sq ft, lower level below-grade at Y sq ft, GLA equals X.

If you have a builder floor plan or a to-scale listing plan, you can trace each level from the image rather than relying solely on field measurements. Set scale from any wall you can verify, and the tool calculates the rest. For split-levels where field access to all levels is sometimes limited, a plan-based measurement backed by a few field verification dimensions is a defensible approach.

Measure each level separately

PlanSnapper lets you trace multiple polygons on the same floor plan, one per level, and get individual square footage for each. Clean documentation for split-levels and multi-story homes.

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Frequently Asked Questions

How do appraisers measure square footage on a split-level home?

Each level is assessed individually. Levels that are entirely above grade count as GLA. Levels partially below grade are excluded from GLA — even if fully finished — and reported as below-grade finished area. The exterior grade line is the determining boundary.

What counts as above grade in a split-level home?

A level is above grade if all exterior walls on that floor are at or above ground level on all sides. If any portion of the exterior wall is below the finished grade, the entire level is considered at least partially below grade and is excluded from GLA.

Why do split-level homes have complicated square footage?

Grade determination can be ambiguous when the ground slopes around the home. Different appraisers may draw the grade line differently, leading to variation in reported GLA. ANSI Z765 provides the standard, but appraiser judgment is still involved in borderline cases.

How many levels does a typical split-level home have?

Most split-level homes have three or four levels offset by half-flights of stairs. Each level must be measured and documented separately on the appraisal form. The appraiser reports GLA by floor and must clearly identify which levels are above grade and which are not.

Does the finished lower level of a split-level count as a basement?

Under ANSI Z765, any level with exterior walls partially below finished grade is treated as below-grade and excluded from GLA. On many split-levels, the lower entry level is partially below grade on at least one side, which disqualifies it from GLA regardless of how finished it is.

Can split-level GLA vary between appraisers on the same property?

Yes — split-levels are one of the most common sources of GLA discrepancy in residential appraisals. The reason is grade interpretation. Two appraisers looking at the same home may draw the grade boundary differently, especially on sloped lots. ANSI Z765 provides guidance, but some judgment is unavoidable.

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