Square Footage & Area calculator.
Calculate square footage or square metres for one room or several mixed shapes, with exclusions and a combined total.
Your dimensions
Measurement schematic, not to scale. Use your own dimensions and product specification.
Use measurements from your plan and properties from your chosen product. Any prefilled values are illustrative.
Square Footage & Area Calculator Net surface area: 600 ft² Area before exclusions: 600 ft² Excluded area: 0 ft² Sections counted: 1 Inputs Measure: One rectangular section Length: 20 ft Width: 30 ft Area to exclude: 0 ft² Formula: Net area = Σ((shape area − excluded area) × count) Assumptions: Measure one rectangle, or add rectangular, circular, triangular and already measured sections. Deduct islands and cut-outs from their own section, then sum non-overlapping areas. A triangle uses perpendicular height; a circle uses its full diameter. This measures area; purchase allowance belongs in the material calculator. Only quantities from supplied dimensions and specifications are calculated. No material-property reference values are bundled; obtain product values from the selected supplier's data sheet. Based on supplied measurements and specifications. No design suitability or code compliance is assessed.
Net surface area
Example estimate · update the inputs for your project
How this result becomes a purchase quantity
These are the actual stages returned by this calculation. Stages with the same quantity and unit are shown once. Additional stages are not invented.
- Area before exclusions: 600 ft²
- Excluded area: 0 ft²
Net area = Σ((shape area − excluded area) × count)
Measure one rectangle, or add rectangular, circular, triangular and already measured sections. Deduct islands and cut-outs from their own section, then sum non-overlapping areas. A triangle uses perpendicular height; a circle uses its full diameter. This measures area; purchase allowance belongs in the material calculator.
Use your chosen material specification. Quantity does not confirm design suitability.
How to use this square footage & area calculator
Calculate square footage for a room, floor, bed or other measured surface. Use one rectangle for a quick calculation or add several shapes to measure an L-shaped or segmented footprint.
- Measure the actual footprint; use the same physical boundary for every section.
- For an L-shaped room, split it into non-overlapping rectangles. Select several sections and enter them separately.
- For a circular section use the full diameter; for a triangle use a base and perpendicular height.
- Subtract an island or cut-out within the section that contains it. Use the combined net area in the appropriate material calculator.
Formula and assumptions
How this calculation works.
Measure one rectangle, or add rectangular, circular, triangular and already measured sections. Deduct islands and cut-outs from their own section, then sum non-overlapping areas. A triangle uses perpendicular height; a circle uses its full diameter. This measures area; purchase allowance belongs in the material calculator.
A worked example
Illustrative inputs only. Product properties and design dimensions are not recommendations for your project.
- Measure
- One rectangular section
- Length
- 4 m
- Width
- 3 m
- Area to exclude
- 0 m²
Net surface area: 12 m²
Before you purchase
Use dimensions from your plan and properties from your chosen product. Any design spacing, section or fixing pattern must already be specified.
Sections must not overlap. Excluded area is deducted within each section before multiplying by thickness or counting identical sections.
Method: dimensional arithmetic and user-supplied specifications. Software checks: 2026-10-04. Calculation and review policy.
A US unit example
An L-shaped floor split into a 12 ft × 10 ft rectangle and a separate 6 ft × 4 ft rectangle measures 120 + 24 = 144 ft². Excluding an 8 ft² island gives 136 ft². This area does not include a material allowance or prove that a cut layout fits.
Common questions
How do I calculate square feet from feet and inches?
Convert each dimension to feet before multiplying. A 10 ft 6 in length is 10.5 ft. The form accepts feet-and-inch entries in US mode and preserves the physical dimensions when switching to metric.
Should I add waste to the measured area?
Keep the measured area separate. Apply your purchase allowance once in the flooring, tile, paint or other material tool that uses this area.
Does this measure the perimeter of a complex outline?
Summing areas does not identify shared edges or an external boundary. Use the Perimeter Calculator with the measured boundary segments.