- Area
- 120 ft²
- Metric area
- 11.15 m²
How it works
Perimeter does not determine floor area
A 10-by-10-foot square and a 5-by-15-foot rectangle both have a 40-foot perimeter, but their areas are 100 and 75 square feet. Measure the sides or component shapes; boundary length alone cannot establish coverage.
Breaking a floor plan into measurable shapes
For an irregular floor plan, divide the area into shapes supported by the calculator and avoid counting overlaps twice. Check whether measurements refer to the interior area or a different boundary. The mixed-unit and cost modes help convert dimensions and apply an entered area price. Material quantities can still require allowances beyond the geometric floor area.
Rectangular area: formula and assumptions
Area = length×width×quantity.
Results include square feet and square meters.
Circular area: formula and assumptions
Area = π(diameter/2)²×quantity.
Use diameter, not radius.
More floor shapes: formula and assumptions
Use the area formula for the selected geometry, then multiply by the quantity.
Border dimensions refer to the outer boundary and the inward border width. All dimensions use feet.
Shapes, mixed units & area cost: formula and assumptions
Convert each length independently, calculate shape area, then apply quantity and the selected area price.
Ring dimensions use outer diameter and inward border. Three-side triangles use a stable Heron calculation. Area pricing is converted using its own unit.
Worked example
Using the Rectangular area example:
- Length (ft)
- 12
- Width (ft)
- 10
- Number of identical areas
- 1
Area = length×width×quantity.
Example result
Area: 120 ft²
Metric area: 11.15 m²
These are illustrative inputs. Change the values to explore a different scenario.
Formula references
References explain the underlying methods; they do not imply endorsement or individual professional review of Finflo.
Common questions
Does circular-area mode use radius or diameter?
The circular modes use diameter, while sector mode uses radius. Follow the selected shape's field labels.
Can each dimension and the area price use different units?
Yes. Mixed-unit mode converts dimensions independently and converts the price's area unit separately before applying quantity and cost.
Prepared by Finflo. See our methodology and editorial policy.