Guides · Floor Plan Measurement

Floor Plan Measurement for Real Estate Investors

For real estate investors, square footage affects every part of underwriting: acquisition price, rent potential, and ARV comparable adjustments. Relying on MLS or county records introduces errors that compound throughout your analysis. Here's how to verify sq ft on acquisition targets fast.

Why investors need independent measurement

MLS square footage is agent-reported and often includes basement space, unheated areas, or spaces that won't count in an appraisal. Example: target listed at 2,800 sq ft. Comps sell at $150/sq ft. ARV model says $420,000. But actual above-grade GLA is 2,200 sq ft — the rest is finished basement. Appraiser uses $150/sq ft for above-grade and $90/sq ft for below-grade. True ARV = (2,200 × $150) + (600 × $90) = $330,000 + $54,000 = $384,000. That's $36,000 less than the model — the difference between a deal and a loss.

Fast workflow for acquisition underwriting

1. From the MLS listing, download or screenshot the floor plan. Most listings now include a CubiCasa, Matterport, or sketched floor plan. 2. Upload to MeasureFloorPlan.com. 3. Trace above-grade living area only. Draw garage and basement as separate polygons if present. 4. Set scale from any labeled dimension. 5. Record: above-grade GLA, basement finished area (if any), garage (if any). 6. Apply appropriate $/sq ft rates for each area type in your underwriting model.

Running multiple comps

For deals where you're comparing multiple properties: spend 5 minutes per property measuring each one. Build a spreadsheet: address, above-grade GLA, below-grade finished area, garage area. Now you have consistent, independently-verified measurements across your entire comp set — not a mix of agent-reported numbers using different inclusion criteria. Your $/sq ft analysis is based on apples-to-apples comparisons.

Before vs after due diligence

Identifying a square footage problem during initial screening (5 minutes) is far better than discovering it after LOI, after inspection, or after the appraisal comes in. Measuring the floor plan is one of the highest-ROI checks in your pre-offer diligence workflow.