# Tile Calculator

> Work out how many tiles you need for a floor or wall from its size, the tile size and grout joint, with a waste allowance and boxes to buy.

Category: Construction · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/tile-calculator

Divide the area by the space each tile takes up, including its share of the grout joint, then add a waste allowance for cuts and breakages.

Also called: Floor tile calculator, Wall tile calculator, Tiling calculator.

## Inputs
- Units (options: Metric (m, cm, mm), Imperial (ft, in); default metric)
- Area length (default 4)
- Area width (default 3)
- Tile length (default 30)
- Tile width (default 30)
- Grout joint (default 3; optional)
- Waste allowance (unit %; default 10; optional)
- Tiles per box (default 10; optional)

## Results
- Tiles to buy
- Boxes
- Tiles that exactly cover the area
- Area
- Area

## Formula

```
Tiles = Area ÷ ((Tile length + Joint) × (Tile width + Joint)) × (1 + Waste%), rounded up;  Boxes = Tiles ÷ Tiles per box, rounded up
```

Where:
- Area: length × width of the surface
- Joint: grout joint width
- Waste%: extra for cuts, breakages and spares

## Worked example
1. Area = 4 × 3 = 12 m². Each tile with a 3 mm joint takes 0.303 × 0.303 = 0.0918 m².
2. 12 ÷ 0.0918 = 130.7 tiles; plus 10% = 143.8, so 144 tiles.
3. 144 ÷ 10 per box = 14.4, so buy 15 boxes.

**Result:** A 4 × 3 m floor in 30 × 30 cm tiles with 3 mm joints needs 144 tiles (15 boxes of 10) including 10% waste.

## What the result means

Buy all tiles from the same batch (shade and size can vary between batches) and keep a few spares for future repairs.

## Assumptions and limits
- A rectangular area. For L-shaped rooms, split into rectangles and add the results.
- The count does not optimise cut pieces; patterned or diagonal layouts typically need 15% or more extra.
- Adhesive and grout quantities are not included.

## Questions

### How much extra tile should I buy?

Around 10% for a straight lay in a simple room is a common allowance; diagonal and herringbone patterns, or rooms with many corners, need more.

### Does the grout joint really matter?

For small tiles, yes. A 3 mm joint on 10 cm tiles adds about 6% to each tile’s footprint, so you need fewer tiles than area ÷ tile size suggests.

## Related calculators
- [Roofing Calculator](https://calculators.geekmidst.com/calculators/roofing-calculator)
- [Concrete Calculator](https://calculators.geekmidst.com/calculators/concrete-calculator)
- [Mulch Calculator](https://calculators.geekmidst.com/calculators/mulch-calculator)
- [Floor Tile Waste Calculator](https://calculators.geekmidst.com/calculators/floor-tile-waste-calculator)

_Quantities are estimates. Confirm requirements with your engineer or supplier before ordering materials._

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/tile-calculator