How many flooring boxes should you buy?
Calculate floor coverage, apply a chosen waste allowance and round up to whole boxes.
Start with net floor area
Measure the intended area and subtract only the exclusions that truly will not be covered. For a rectangular 5 m by 4 m room with no exclusions, the area is 20 m². Check that the product’s box coverage is also expressed in square metres.
Apply the chosen allowance
If you choose a 10% allowance, the coverage target becomes 20 × 1.10 = 22 m². Layout, cuts, patterns and spare material can affect the allowance you choose. This percentage is an example; ask the installer or supplier what suits the actual job.
Compare the example
20 m² net floor area; 1.8 m² coverage per box
| Chosen allowance | Coverage target (m²) | Whole boxes | Purchased coverage (m²) |
|---|---|---|---|
| 0% | 20.0 | 12 | 21.6 |
| 5% | 21.0 | 12 | 21.6 |
| 10% | 22.0 | 13 | 23.4 |
On a small screen, scroll the table sideways if needed.
Try this in the calculator
Use a 5 m × 4 m room, zero exclusions and 1.8 m² per box. Compare allowances of 0%, 5% and 10%. Choose an appropriate allowance with your installer rather than treating the examples as recommendations.
Try the example ↗Round up after dividing
With 1.8 m² per box, 22 ÷ 1.8 ≈ 12.22 boxes. You need 13 whole boxes to meet that target. Those boxes cover 23.4 m², so the purchased coverage exceeds the target by 1.4 m². The extra is a consequence of whole-box ordering.
Keep cost units aligned
At 35 currency units per box, 13 boxes cost 455 before any separately charged delivery or materials. Do not enter a price per square metre into a field asking for price per box. Product coverage and pricing units are independent pieces of information.
Confirm the product and exclusions
Check the coverage printed for the exact product, the intended laying pattern and any return conditions. The estimate does not include adhesive, underlay or trim unless you account for them separately. Save your dimensions and allowance so you can revisit the order if the product changes.