Tile Calculator
Work out how many tiles and boxes you need, including waste allowance and grout.
About Tile Calculator
Tiles required equals the room area divided by the area of one tile, rounded up. A waste factor covers cuts and breakage — 10% for a straight lay, 15% for a 45° diagonal, up to 20% for complex patterns. Boxes are rounded up to the nearest whole box. Grout consumption is estimated with the formula (W + H)/(W × H) × joint_width × tile_depth × 1.44, which derives from the volume of the grout joints and a density factor for Portland-cement-based grout.
Formulas
Tiles required
Tiles = ceiling(room_area ÷ tile_area × (1 + waste%))
Grout (lb/sq ft)
Grout lb/sq ft = (tile_length + tile_width) / (tile_length × tile_width) × joint × depth × 1.44
- T_L
- Tile length (in)
- T_W
- Tile width (in)
- J
- Joint width (in)
- D
- Tile depth (in)
Worked example
With the default values below, Tile Calculator returns Tiles Needed of 132. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Area Lengthminimum 0.1 ft
- 12 ft
- Area Widthminimum 0.1 ft
- 10 ft
- Tile Lengthminimum 1 in
- 12 in
- Tile Widthminimum 1 in
- 12 in
- Tiles per Boxminimum 1
- 10
- Waste Factoraccepts 0–30 %
- 10 %
- Grout Joint Widthaccepts 0.063–1 in
- 0.125 in
- Tile Thicknessaccepts 0.125–2 in
- 0.375 in
Results
- Tiles NeededRounded up, includes waste.
- 132
- Boxes NeededRounded up.
- 14
- Room Area
- 120.00 sq ft
- Area per Tile
- 1.0000 sq ft
- Grout Needed
- 1.5 lb
Step by step
- 1Room area= 120.00 sq ft
- 2Area per tile= 1.0000 sq ft
- 3Tiles required (net)= 120.0 tiles
- 4Add 10% waste= 132.0 → 132 tiles
- 5Boxes= 14 boxes
- 6Grout estimate= 1.48 lb
Assumptions and limits
- The result is derived only from the 8 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
Why should I add waste to my tile count?
Tiles need to be cut at walls, corners and obstacles. Some tiles crack during installation. 10% waste is a safe minimum for simple straight-lay floors. Increase to 15–20% for diagonal or complex patterns where cuts waste more material.
How do I find 'tiles per box'?
Check the tile carton label — it lists how many tiles and the coverage area. Enter that number in the 'Tiles per Box' field.
How accurate is the grout estimate?
The formula gives a good approximation for standard Portland-cement grout. Epoxy grouts and specialty mixes have different densities. Check the manufacturer's yield chart for precision.
Does this work for wall tiles?
Yes — measure the wall area (height × width) as you would a floor, and the calculation is identical.