BuildCalcs Step 1: measure net floor area
A 4.2 m × 3.6 m rectangular room is 15.12 m². For alcoves or connected spaces, calculate each rectangle separately and add them. This gives an auditable measurement rather than one guessed total.
Step 2: choose an allowance consciously
| Measured area | +5% | +10% | +15% |
|---|---|---|---|
| 5 m² | 5.25 m² | 5.50 m² | 5.75 m² |
| 10 m² | 10.50 m² | 11.00 m² | 11.50 m² |
| 15 m² | 15.75 m² | 16.50 m² | 17.25 m² |
| 20 m² | 21.00 m² | 22.00 m² | 23.00 m² |
| 25 m² | 26.25 m² | 27.50 m² | 28.75 m² |
| 30 m² | 31.50 m² | 33.00 m² | 34.50 m² |
| 40 m² | 42.00 m² | 44.00 m² | 46.00 m² |
The table does not claim that one percentage is correct. Straight layouts, diagonal patterns, awkward shapes and products with unusable offcuts can have different requirements.
Step 3: convert to packs
If the adjusted requirement were 16.63 m² and a pack covered 2.20 m², 16.63 ÷ 2.20 = 7.56 packs. Because partial packs may not be purchasable, the mathematical purchase quantity becomes 8 packs, assuming the stated pack coverage is correct.
Worked example
For the 15.12 m² room, a 10% allowance gives 16.632 m². With 2.20 m² packs, the result is 7.56 packs → 8 packs. Eight packs provide 17.60 m², so the effective spare area after pack rounding is 2.48 m² above the measured room.
Why pack rounding matters
Applying a percentage and then rounding packs is not the same as simply buying “10% extra”. Small rooms and large pack sizes can create a noticeably larger effective allowance. Showing both values makes the result easier to understand.
Things to verify
- Actual coverage printed for the selected pack.
- Whether the pattern increases cutting.
- Whether offcuts can be reused.
- Whether you want spare matching material for future repairs.
Enter your actual measurements rather than relying on a generic example.
Open the Flooring Calculator →