How to Measure a Split-Level Floor Plan
Split-level homes divide living space across three or more staggered levels, connected by short stairways. Measuring square footage accurately requires understanding which levels are above grade, how to handle the mid-level entry, and how to total separate floor plan sections correctly.
What is a split-level home?
A split-level (also called a bi-level or tri-level) home staggers its floors so that no two main living areas are on the same level. Entering at grade level, you typically go up a half-flight to the main living area and down a half-flight to a lower level that sits partially below grade. Some split-levels add a third level above the main floor.
The defining characteristic is the staggered floor plan: instead of a single ground floor and a full second story, the home has offset levels. This affects both how you obtain the floor plan and how you measure it.
Getting a floor plan for a split-level home
Split-level floor plans are typically presented as separate diagrams for each level — upper level, main level, and lower level. Services like CubiCasa, iGUIDE, and Matterport produce individual floor plan images per level. If you are working from an architect drawing or county record, each level should have its own sheet.
If you only have a combined floor plan showing all levels together, you may need to measure each section separately, being careful not to double-count overlap areas between staggered levels.
Above-grade vs. below-grade in split-level homes
For appraisal purposes (ANSI Z765-2021 and Fannie Mae guidelines), the classification of each level matters significantly. Gross Living Area (GLA) only includes above-grade finished space. The key rule: a level is above grade only if its entire floor is at or above the exterior grade (ground level) on all four sides.
- Upper level: Almost always above grade — counts as GLA.
- Main level: Usually above grade — counts as GLA if the floor is entirely above grade.
- Lower level: Often partially or fully below grade. If any portion of the exterior walls is below ground level, the entire level may be classified as below grade and excluded from GLA.
In practice, many split-level lower levels are finished and livable but cannot be counted in GLA per ANSI standards. Appraisers report below-grade finished area separately as its own line item — it still contributes to value, just not as GLA.
How to measure each level
Measure each level of the split-level home as a separate floor plan. For each level:
- Upload the floor plan image for that level
- Trace the exterior perimeter of the finished living area
- Set one known wall dimension as your scale reference
- Note the calculated square footage for that level
- Repeat for each additional level
If a level wraps under or over another level, measure only the footprint of that level — not the combined area. Each level is measured independently.
Totaling the square footage
After measuring each level separately, total them according to classification:
- GLA: Sum of all above-grade finished levels (upper + main for most splits)
- Below-grade finished area: Lower level square footage (if finished but classified below grade)
- Total finished area: GLA + below-grade finished area
For a listing or homeowner use, total finished area is typically more meaningful. For an appraisal report using ANSI standards, GLA and below-grade area are reported separately.
Common split-level measurement mistakes
- Measuring the garage as living area: The lower level of a split-level often includes an attached garage. Exclude the garage footprint from your living area measurement.
- Including stairways in both levels: Stairway openings create voids in the floor above. When measuring the upper level, exclude the open stairway void if it is significant.
- Assuming all levels are above grade: Walk the exterior of the home to confirm which walls are fully above grade before classifying levels for GLA.
- Using a single scale reference for multiple levels: Each level should be set to scale independently, especially if the floor plan diagrams are at different scales.
Scale reference for split-level floor plans
To set the scale for each level, you need at least one known wall dimension on that level. A common approach is to use an exterior wall dimension noted on the floor plan, or to measure a single wall in person and enter it as the scale reference. If the floor plans were produced by a scan service, the scale is usually printed on the plan — but always verify by entering a known dimension rather than trusting the printed scale alone.
Try the tool
Upload your split-level floor plans — one at a time per level — trace each perimeter, set your scale reference, and record the result for each. The total takes about two minutes per level. Start measuring →