Area Calculator
Calculate rectangular area from length and width.
Calculation example
Inputs: Length: 20 ft, Width: 15 ft
Result: 300 square units
A 20 by 15 rectangle has an area of 300 square units.
Formula
Area = length × width.
How to use this calculator
Multiply length by width using the same unit for both measurements.
Before you calculate
Measure the project dimensions as accurately as practical and keep all measurements in compatible units. For material products, use the coverage, yield, density, or package size stated by the manufacturer or supplier rather than a generic assumption.
Choose the waste allowance based on the project shape, installation method, cutting requirements, and material characteristics. A simple rectangular estimate may need adjustment for openings, corners, slopes, joints, patterns, compaction, or other site conditions.
Understanding the result
The calculator provides a planning estimate based on the inputs shown above. It is not a substitute for project drawings, structural design, manufacturer instructions, or local requirements. Before ordering, compare the calculated quantity with the supplier's package sizes and ordering units.
Tips
- Use the actual finished dimensions.
- Irregular areas may need to be split into multiple rectangles.
Frequently asked questions
How is rectangular area calculated?
Length is multiplied by width.
What if the shape is irregular?
Split it into simple shapes and add their areas.
Related calculators
Use compatible units and verify estimates against project specifications, local requirements and manufacturer instructions.