Floor & volume
Split an irregular footprint into non-overlapping rectangles.
- Floor area is the sum of section areas; volume multiplies that area by the common height. Shared edges are not included in a perimeter estimate.
Home & DIY calculator
Room Measurements
Combine rectangular sections and measure floors, walls, openings and room volume.
What does a worked calculation look like?
A 5 × 4 m room has a floor area of 20 m² and, at 2.5 m high, a volume of 50 m³. Its walls (two of 5 × 2.5 m and two of 4 × 2.5 m) total 45 m², or 40.3 m² after subtracting 4.7 m² of openings.
Method and practical checks
- Floor area is the sum of section areas; volume multiplies that area by the common height. Shared edges are not included in a perimeter estimate.
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Every calculation option
Wall area
Measure each wall group and subtract the actual total opening area.
- Wall area sums length × height × count. Measure door and window openings; do not subtract an opening twice.
Worked example
A 5 × 4 m room has a floor area of 20 m² and, at 2.5 m high, a volume of 50 m³. Its walls (two of 5 × 2.5 m and two of 4 × 2.5 m) total 45 m², or 40.3 m² after subtracting 4.7 m² of openings.
| Input | Value |
|---|---|
| Measured sections | Length 5 m, Width 4 m |
| Room height | 2.5 m |
| Result | Value |
|---|---|
| Floor area | 20 m² |
| Room volume | 50 m³ |
Reading the result
- For L-shaped or irregular rooms, add each rectangle as a separate row so no area is counted twice.
- Floor area feeds flooring and tiles; net wall area feeds paint and wallpaper.
- Room volume is useful for heating, ventilation and dehumidifier sizing, but those products specify their own requirements.
How do I measure an L-shaped room?
Split it into non-overlapping rectangles, calculate each area and add them. Do not count the overlapping corner twice. Measure the finished dimensions and keep your units consistent; use the separate wall mode when you need wall covering rather than flooring.
Why is a buying allowance separate from measured area?
Measured area describes the space. An allowance describes extra material for cuts, breakage or uncertain measurements. Keeping them separate lets you inspect the real dimensions and choose an allowance appropriate to the product instead of quietly enlarging every room measurement.
Can I use the room's perimeter instead of its area?
No. Area describes a surface in square metres, while perimeter describes its boundary in metres. A rectangular 4 m by 3 m floor has 12 m² of area and a 14 m perimeter. Choose the result that matches the material: floor covering uses area, whereas trim commonly uses a measured length.
Calculation/content reviewed 4 October 2026. Source: Babushka Market’s displayed formulas, units and labelled editable assumptions. How the estimates work