# Tile Calculator

Calculate the number of tiles needed for your floor or wall. Enter room dimensions, tile size, and wastage. Includes grout gap adjustment.

## What this calculates

Avoid running short or over-buying tile for your project. This calculator determines the exact number of tiles you need based on room dimensions, tile size, grout gap width, and a wastage percentage for cuts and breakage. It gives you the precise count to order, including box estimates.

## Inputs

- **Room Length** (ft) — min 0
- **Room Width** (ft) — min 0
- **Tile Length** (in) — min 0.1
- **Tile Width** (in) — min 0.1
- **Wastage** (%) — min 0, max 50 — Extra tiles for cuts and breakage. 10% for straight layouts, 15% for diagonal.
- **Grout Gap Size** (in) — min 0, max 1 — Width of grout lines between tiles

## Outputs

- **Room Area** (ft²)
- **Single Tile Area** (in²)
- **Tiles Needed (exact)** — Without wastage
- **Tiles to Order** — Including wastage percentage
- **Boxes (at 10 tiles/box)** — Based on a standard box of 10 tiles
- **Total Tile Area to Order** (ft²)

## Details

The calculation accounts for both tile size and grout gaps:

  - Room area = length × width (in square feet)

  - Effective tile area = (tile length + grout gap) × (tile width + grout gap), converted to square feet

  - Tiles needed = room area / effective tile area, rounded up

  - Tiles to order = tiles needed × (1 + wastage %)

Recommended wastage percentages:

  - Straight (grid) layout: 10% wastage

  - Diagonal (45°) layout: 15% wastage

  - Herringbone or complex patterns: 15-20% wastage

  - Large format tiles in small rooms: 15% (more cuts needed)

Common tile sizes: 12×12", 18×18", 24×24" for floors; 3×6", 4×12", 6×24" for subway/wall tiles. The grout gap is typically 1/16" to 1/4" depending on tile type and style.

## Frequently Asked Questions

**Q: How much wastage should I account for?**

A: 10% for standard straight (grid) layouts in regularly shaped rooms. Use 15% for diagonal layouts or rooms with many corners and obstacles. Complex patterns like herringbone may need 15-20%.

**Q: Why does grout gap size matter?**

A: Grout gaps add to the effective tile size. A 12-inch tile with 1/8-inch grout gaps effectively covers 12.125 inches per tile. Over a large area, this reduces the number of tiles needed slightly. Ignoring grout gaps leads to over-ordering.

**Q: How many 12x12 tiles do I need per square foot?**

A: Exactly 1 tile per square foot (since 12 inches = 1 foot, and 12×12 inches = 1 ft²). For 6×6 tiles, you need 4 per square foot. For 18×18 tiles, you need 0.44 per square foot.

**Q: Should I buy extra tiles beyond the wastage?**

A: Yes, consider buying an extra 2-3 tiles beyond the calculated amount. Tile colors can vary between production batches, so having spares from the same batch is valuable for future repairs.

**Q: How do I tile around obstacles like toilets or columns?**

A: Measure the obstacle footprint and subtract it from the room area, or simply keep the default wastage percentage, which accounts for cuts around obstacles. Complex cuts around curved obstacles waste more material.

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Source: https://vastcalc.com/calculators/construction/tile
Category: Construction
Last updated: 2026-04-21