How to read this result
In the default example, average comp price/sq ft is $251.67. Results describe this input scenario; they are not a recommendation.
Change one assumption at a time to see how it affects the scenario. Compare periods and cost definitions consistently. Negative results show a modeled shortfall; an unavailable ratio needs a valid denominator.
Formula and methodology
Average the three comparable price-per-square-foot figures, then multiply by the subject area. All figures must use compatible area definitions and comparable property conditions.
Enter percentages as whole numbers: 5 means 5%. When used as a factor, the calculation divides a percentage by 100. Percentage outputs multiply the final ratio by 100. Calculations retain precision internally; displayed amounts and rates are rounded to two decimals.
Variables and input definitions
- Subject square feet (sq ft)
- Subject living/rentable area using a consistent measurement basis. Minimum: 1.
- Comp 1 price per sq ft (USD/sq ft)
- Adjusted comparable unit price. Minimum: 0.
- Comp 2 price per sq ft (USD/sq ft)
- Adjusted comparable unit price. Minimum: 0.
- Comp 3 price per sq ft (USD/sq ft)
- Adjusted comparable unit price. Minimum: 0.
Worked example
This example uses the exact prefilled inputs above. Reset defaults to restore this scenario after making changes.
| Item | Default scenario |
|---|---|
| Subject square feet | 2,000 |
| Comp 1 price per sq ft | $250.00 |
| Comp 2 price per sq ft | $260.00 |
| Comp 3 price per sq ft | $245.00 |
| Item | Default scenario |
|---|---|
| Average comp price/sq ft | $251.67 |
| Indicated subject value | $503,333.33 |
Assumptions and limitations
Price-per-square-foot is a simplified comp method and should not replace full adjustment analysis.
Results describe this input scenario; they are not a recommendation.
The tool uses values you supply. It does not retrieve market prices, verify leases or inspect a property. Results exclude items outside the listed inputs. Review local requirements and the relevant contract when a payment, fee or allocation depends on them.
Common mistakes
Price per square foot can differ with lot value, size, condition and location. It is not a universal scaling law; do not mix rentable and gross building area.
Sources and method references
These references provide context for the method and terminology. They do not endorse this tool or validate your property assumptions.
- IRS — Instructions for Form 709 (2025) — real property valuationComparable-sales concept and adjusting for differences in date, size, condition and location.
- IRS — Publication 551 (12/2025), Basis of AssetsFair-market-value concept and use of similar-property sales as evidence.
Frequently asked questions
Do larger properties always have the same price per square foot?
No. Size, land contribution and property characteristics can change the metric. Use genuinely comparable evidence.
Does this adjust individual comparable sales?
No. Enter already reviewed comparable price-per-square-foot figures. The tool averages them and scales the result by subject area.