MetraNestStart by drawing the outer rectangle
Imagine a rectangle surrounding the entire room. Measure its overall length and width. Then measure the length and width of the cut-out: the missing rectangle in one corner. Each cut-out dimension must be smaller than the corresponding outer dimension.
Another method to cross-check
You can also divide the room into two non-overlapping rectangles, calculate each area and add the results. Both methods should give the same area. If they differ, check the length of one arm of the L or an area counted twice.
What the result tells you
The geometric area is a starting point for flooring, a cleaning estimate or a room layout. It includes no cutting allowance. To buy wood flooring or tiles, transfer it to the relevant tool and then choose an allowance suited to the installation plan.
L-shaped area = outer length × outer width − cut-out length × cut-out width.
A living room with a missing corner
The outer rectangle measures 5 × 4 m, or 20 m². The cut-out measures 2 × 1.50 m, or 3 m². The room therefore covers 17 m². A check using two rectangles gives 5 × 2.50 m + 3 × 1.50 m = 17 m².
Details to check
- Keep the measurements taken on site without rounding them too early.
- Show the cut-out on your sketch.
- For several cut-outs, divide the room into separate rectangles.
Frequently asked questions
Can this tool calculate a room with angled corners?
No. The model assumes right angles. A diagonal or curved wall needs a different geometric breakdown.
Can skirting be calculated from this area?
No. Skirting follows the perimeter. Keep the wall lengths to calculate its quantity separately.
Method and references · Editorial review: 25 October 2026
The geometric formulas are explained here. For a product, its packaging dimensions and coverage rate remain the reference inputs.