Floor Calculator
Floor calculator works out Base area and Waste-adjusted area to buy from What to work out, Room length and Room width. The default figures on this page give estimated total cost of 840.00; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
3 steps
- Base area = 12 x 10 = 120
- Purchase area = 120 x (1 + 0/100) = 120
- Total = material 480 + labour 360 + fixed fees 0 = 840
Its 5 worked examples are re-run on every release, last on 15 September 2026. What changed
Keep this result
Save it, change one figure, then compare the two
The calculation stays free. Save this scenario, adjust one assumption, save that too, and put them side by side to see exactly what the change costs you. A free account keeps 5 scenarios and 2 comparisons; Personal makes both unlimited and adds exports and private links. Nothing is saved unless you press Save.
What the floor calculator calculates
Turns a room measurement into a waste-adjusted purchase area and then into whole tiles, whole flooring packages, or a carpet and installation cost estimate from your own unit prices.
How to use this floor calculator
Enter What to work out, Room length, Room width and Net floor area. Base area updates as you type, and “Use a worked example” loads checked figures you can adjust. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Base area, Waste-adjusted area to buy and Tiles.
The method follows OpenStax, Elementary Algebra 2e, Solve Geometry Applications: Volume and Surface Area (rectangular area = length x width) and NIST Special Publication 811, Appendix B.9 (exact length and area conversion factors).
Research R383-GT-1: 10 m2 of 0.25 m2 tiles example
With Net floor area: 10, Tile face area: 0.25, Waste allowance: 0, the calculator returns Tiles: 40, Base area: 10, Waste-adjusted area to buy: 10. This example is checked against an independent source in the test suite.
What you can compare
Change one input at a time to see how it affects Base area, Waste-adjusted area to buy and Tiles. The inputs you can vary are What to work out, Room length, Room width, Net floor area, Tile face area and Tile length.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
How do I calculate how much floor I need?
Turns a room measurement into a waste-adjusted purchase area and then into whole tiles, whole flooring packages, or a carpet and installation cost estimate from your own unit prices. Open “How this is worked out” beside the result to see each step for your own figures.
What is the formula for calculating flooring?
Turns a room measurement into a waste-adjusted purchase area and then into whole tiles, whole flooring packages, or a carpet and installation cost estimate from your own unit prices. On this page it is computed from What to work out, Room length and Room width and shown as Base area, Waste-adjusted area to buy and Tiles.
How much flooring is needed for a 10x10 room?
On the figures this page opens with — net floor area 10, tile face area 0.25 and waste allowance 0% — the estimated total cost is 840. No single number fits everyone: change any figure above and the answer updates as you type, with each step of the arithmetic beside it.
What information do I need for the floor calculator?
You need What to work out, Room length, Room width, Net floor area, Tile face area, Tile length, Tile width and Grout joint width. The page opens with default figures that give estimated total cost of 840.00, so you can see the scale before entering your own.
What does this floor calculator show?
It shows Base area, Waste-adjusted area to buy, Tiles, Packages, Tile module area (tile plus grout joint), Material cost, Labour cost and Estimated total cost, with the working and any warnings for your entries.
Can I check how the floor calculator result was calculated?
Yes. The “How this is worked out” section shows the calculation steps, and the sources section identifies the references used for the method.