Formula
- Floor area = room length × room width.
- Area to buy = floor area × (1 + allowance ÷ 100); packs = area to buy ÷ coverage per pack, rounded up.
Assumptions and limits
- Packs round up to whole packs.
Home & DIY calculator
Flooring Calculator
Estimate floor area and packs including waste.
What does a worked calculation look like?
A 5 × 4 m room has 20 m² of floor. With a 10% cutting allowance you need 22 m², and packs covering 2.2 m² each mean exactly 10 packs.
Example with the pre-filled values
Floor area (m²): 20 · Area including cutting allowance (m²): 22 · Packs to buy: 10
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Worked example
A 5 × 4 m room has 20 m² of floor. With a 10% cutting allowance you need 22 m², and packs covering 2.2 m² each mean exactly 10 packs.
| Input | Value |
|---|---|
| Room length | 5 m |
| Room width | 4 m |
| Coverage per pack | 2.2 m² |
| Waste | 10 % |
| Result | Value |
|---|---|
| Floor area (m²) | 20 |
| Area including cutting allowance (m²) | 22 |
| Packs to buy | 10 |
Reading the result
- 10% is typical for straight-laid boards in a simple room; herringbone, diagonal laying or many corners need more.
- Measure into door recesses and alcoves; add them as part of the length or width or calculate them separately.
- If the result is a whole number of packs, there is no spare. Consider one extra pack for repairs.
When should I round the flooring quantity?
Calculate the measured area and allowance first, then round up to complete packs using the printed pack coverage. Rounding each measurement early can compound errors. Keep a separate plan for underlay, trims and thresholds because their pack sizes and waste differ from the flooring.
Does room area account for laying direction?
Area establishes a starting quantity, but the cutting plan affects waste. Narrow end pieces, diagonal layouts and patterns can use more material. The waste percentage is editable; compare the result with the supplier's installation instructions and your room-by-room layout. Plan diagonal cuts explicitly.
What should I do with the calculated spare flooring?
Treat the difference between purchased pack coverage and planned coverage as a separately reported remainder. Some may cover cuts or later repairs, but it is not automatically all waste. Check batch consistency and storage needs before ordering; pack rounding describes a purchase quantity rather than a complete installation layout.
Calculation/content reviewed 4 October 2026. Source: Babushka Market’s displayed formulas, units and labelled editable assumptions. How the estimates work