- Area
- 20 m²
How it works
Convert both dimensions before multiplying
A rectangle 2 m long and 50 cm wide covers 1 m², or 10,000 cm². Multiplying the unconverted numbers gives 100 with incompatible units; the independent unit selectors prevent that mismatch.
Selecting the shape that matches the measurement
Area formulas depend on the shape and on whether a height is perpendicular to the relevant base. Choose the matching shape before entering measurements. For an irregular region, calculate suitable pieces separately rather than forcing it into an unrelated formula. Check the output's squared unit and avoid treating a side length or perimeter as an area input.
Rectangle: formula and assumptions
A = length × width.
Enter positive dimensions in one consistent unit. The result is in square units. Each dimension can use its own unit. Results use the selected output unit with the appropriate square or cube.
Triangle: formula and assumptions
A = base × height / 2.
Enter positive dimensions in one consistent unit. The result is in square units. Each dimension can use its own unit. Results use the selected output unit with the appropriate square or cube.
Trapezoid: formula and assumptions
A = (a+b) × height / 2.
Enter positive dimensions in one consistent unit. The result is in square units. Each dimension can use its own unit. Results use the selected output unit with the appropriate square or cube.
Circle: formula and assumptions
A = πr².
Enter positive dimensions in one consistent unit. The result is in square units. Each dimension can use its own unit. Results use the selected output unit with the appropriate square or cube.
Sector: formula and assumptions
A = πr² × angle / 360.
Enter positive dimensions in one consistent unit. The result is in square units. Each dimension can use its own unit. Results use the selected output unit with the appropriate square or cube. Angular inputs can use degrees or radians. Calculated angles are shown in degrees.
Ellipse: formula and assumptions
A = πab.
Enter positive dimensions in one consistent unit. The result is in square units. Each dimension can use its own unit. Results use the selected output unit with the appropriate square or cube.
Parallelogram: formula and assumptions
A = base × height.
Enter positive dimensions in one consistent unit. The result is in square units. Each dimension can use its own unit. Results use the selected output unit with the appropriate square or cube.
Triangle from three sides: formula and assumptions
s = (a+b+c)/2; area = √[s(s−a)(s−b)(s−c)].
The sum of any two sides must exceed the third. Angles are calculated from normalized side geometry. Altitudes, medians, radii and centers are also shown in coordinates A=(0,0), B=(c,0), with C above the x-axis. Each dimension can use its own unit. Results use the selected output unit with the appropriate square or cube.
Worked example
Using the Rectangle example:
- Length
- 5
- Length unit
- Meters
- Width
- 4
- Width unit
- Meters
- Result length unit (squared for area, cubed for volume)
- Meters
A = length × width.
Example result
Area: 20 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
Is a triangle's height the same as its sloping side?
Not usually. Base-and-height area uses the perpendicular distance to the base. Use the three-side mode when only side lengths are known.
Can dimensions use different length units?
Yes, when the unit selectors are used correctly. The engine converts each dimension and expresses area in the selected square unit.
Prepared by Finflo. See our methodology and editorial policy.