Calculate a rectangle area or find a missing side. Optional links route material-specific work to the appropriate calculator.
What are you measuring?
| Example | Result |
|---|---|
| 5 m × 4 m | 20 m² |
| 10 m × 3 m | 30 m² |
| 20 m² ÷ 4 m | 5 m |
Describe the task to the AI assistant and continue from the result.
Open AI assistant →Simple rectangle area
Multiply length by width to get square metres. If area and one side are known, divide area by that side.
Choose the next tool only when needed
Tile, concrete, gravel and decking calculations need additional inputs. The route block links to those specialist calculators without delaying the basic result.
Important limit
This page calculates geometry only and does not assume openings, waste, material density or structural requirements.
When one rectangle is not enough
For a rectangular area, convert both dimensions to metres and multiply them. Repeated pieces are handled the same way: find the area of one piece, then multiply by the quantity. If a wall, floor or plot has an irregular outline, split it into simple rectangles or triangles, calculate each part and add the results. A total area by itself does not determine one unique length and width, and room volume is a different calculation because height is also required.