Measurement & Materials
Area and square footage
Measure rectangles, triangles, circles and trapezoids; combine sections and subtract cutouts to find net square footage.
Your inputs
Complete the fields for your selected method. Zero means intentionally zero, not unknown. Currency selection labels amounts; it does not convert exchange rates.
How this calculation works
rectangle = a × b; triangle = a × b / 2; circle = π × (a / 2)²; trapezoid = (a + b) × height / 2; net area = additions - deductions
A quantity estimate from your measurements, not a drawing takeoff, layout optimization, engineering design or code approval. Keep overlapping sections out of the total. Material allowances are your assumptions; supplier package sizes, product coverage and prices must come from the actual product or quote. Optional prices entered as zero are omitted; cost subtotals include only entered prices. Triangle heights must be perpendicular to the base. Trapezoid A and B must be parallel. Break irregular shapes into measured simple sections; side lengths alone do not determine every irregular area.
What information do I need?
Use records for the same job, equipment or accounting period. Only the fields for your selected entry method are required. An unknown amount is not zero.
Input definitions and where to find them
- Measured shapes — circle uses diameter A; triangle uses perpendicular height B: Use matching records or an explicitly identified assumption for measured shapes — circle uses diameter a; triangle uses perpendicular height b. Unknown is not the same as zero.
- Shape name: Use matching records or an explicitly identified assumption for shape name. Unknown is not the same as zero.
- Shape: Use matching records or an explicitly identified assumption for shape. Unknown is not the same as zero.
- Add or subtract this shape: Use matching records or an explicitly identified assumption for add or subtract this shape. Unknown is not the same as zero.
- Length / base / diameter A (ft): Measure this distance. Choose feet, inches or meters beside the field; decimal feet and decimal inches are accepted. Use the feet-and-inches tool to convert fractions if needed.
- Width / perpendicular height / second parallel side B (ft): Measure this distance. Choose feet, inches or meters beside the field; decimal feet and decimal inches are accepted. Use the feet-and-inches tool to convert fractions if needed.
- Trapezoid perpendicular height (ft): Measure this distance. Choose feet, inches or meters beside the field; decimal feet and decimal inches are accepted. Use the feet-and-inches tool to convert fractions if needed.
Use the Where to find this value controls beside the inputs for available work-it-out helpers. Estimates remain your assumptions; a helper does not verify the source figures.
Worked example
Example amounts use US dollars (USD).
Example answer: Net measured area is 120.00 ft² for the illustrative inputs below.
Example inputs
- Measured shapes — circle uses diameter A; triangle uses perpendicular height B
- Shape name: Room
- Shape: Rectangle
- Add or subtract this shape: Add area
- Length / base / diameter A: 12.00 ft
- Width / perpendicular height / second parallel side B: 10.00 ft
- Net measured area
- 120.00 ft²
- Net area in square yards
- 13.33 yd²
- Net area in square meters
- 11.15 m²
- Net area in acres
- 0.002755 acres
- Added area before cutouts
- 120.00 ft²
- Subtracted cutouts
- 0.00 ft²
These illustrative values are not recommended rates or industry averages. Replace every example input with your own figures.
Use the result well
Use the net measured quantity to check a material order or quote. Keep installed area, extra material and purchased quantities separate.
Keep inputs on the same scope and time basis. Calculations retain precision internally; displayed values generally round to two decimal places, with extra precision for very small values and whole-unit rounding where required. Economic comparisons describe your supplied assumptions and do not guarantee future results.
This tool provides business arithmetic. It does not approve engineering designs, establish legal or tax treatment, select equipment or certify safe operating conditions.