Rectangle area
5 × 4
Area = length × width
Formula
Length × width
How the calculation works
Calculate the area of a rectangle from its length and width. Enter each measurement in the unit shown beside the input. The result updates when you change a value; incomplete or unsupported inputs display an explanation.
Worked example
A 5 m by 4 m rectangle has an area of 20 m².
When to use this calculator
Use this for rectangular surfaces, plots, and simple plans.
Common mistakes and limits
Area is measured in square units. A sloped or irregular surface needs a different method.
Check your result
Check that all measurements describe the same object or time period. Repeat the calculation with unrounded values, then round only the final quantity to a precision suitable for the task.
Frequently asked questions
Does this calculator need an account?
No. Calculations run in your browser without an account.
How precise is the displayed result?
The display rounds to six decimal places. Measurement uncertainty can be larger than this rounding.
