Summary
Calculate area for rectangles, squares, triangles, circles, and trapezoids.
Calculation details
Only the positive dimensions required by the selected shape are validated. Calculations retain raw JavaScript number precision; display values are rounded to at most six decimal places.
Formula
Rectangle lw; square s²; triangle bh/2; circle πr²; trapezoid (a+b)h/2.
Worked example
Area Calculator example
A 5 m by 4 m rectangle has area 20 m².
How it works
Select a shape, then enter only the positive dimensions that shape needs. Other dimension fields are not validated for unused modes.
Frequently asked questions
How accurate is the Area Calculator?
The calculation keeps raw numeric precision and rounds only the displayed result to at most six decimal places.
What should I do with an invalid result?
Check that every visible value is finite and that no required divisor is zero.