What waste percentage should I use?

For a standard straight lay, use 10%. For a diagonal (45°) or herringbone pattern, use 15–20% because more cuts are needed. Add an extra 5% if the tiles are large-format or your room has many obstacles.

Should I measure the room in feet or meters?

Use whatever unit is on your tape measure. The calculator accepts inches, feet, centimeters, and meters — just make sure all fields use the same unit.

Do I need to include the grout joint?

For a quick estimate, grout joints are often ignored because they slightly increase coverage. For precision, enter your intended grout joint width (typically 1/8 in or 3 mm for floor tiles).

How are boxes calculated?

Enter the number of tiles per box printed on the product packaging. The calculator divides the total tiles needed (including waste) by that number and rounds up to the nearest whole box.

Does the calculator handle non-rectangular rooms?

Break a non-rectangular room into rectangular sections, calculate each section separately, and add the totals together. Subtract any area you will not tile (e.g. a bathtub footprint).

Tile Calculator

Name: Tile Calculator
Availability: InStock
Author: Nham Vu

Enter room dimensions and tile size to instantly calculate how many tiles you need, including waste allowance.

Room & Tile Dimensions

Unit of measurement

Inches Feet Centimeters Meters

Room dimensions

Length

Width

Tile dimensions

Tile length

Tile width

Grout joint width (optional)

Typical: 0.125 in / 3 mm for floor tiles

Waste allowance 10%

0% 10% straight lay 30%

Tiles per box (optional)

Fill in the dimensions and click Calculate

Summary

Enter room dimensions and tile size to instantly calculate how many tiles you need, including waste allowance.

How it works

Enter the room length and width in your preferred unit (inches, feet, centimeters, or meters).
Enter the tile length and width in the same unit.
Optionally include a grout joint width to account for spacing between tiles.
Set the waste percentage (10% is standard for straight lays; 15–20% for diagonal or complex cuts).
The calculator shows total area, tiles needed, tiles including waste, and boxes to buy.

Use cases

Plan a bathroom floor or wall tile project before visiting the store.
Estimate material costs by knowing the exact number of tiles required.
Account for tile cuts along edges and breakage during installation.
Calculate how many boxes to purchase based on your tile brand pack size.
Compare different tile sizes to see which fits a room with less waste.
Re-estimate after changing grout joint width or tile layout angle.
Provide clients with an accurate tile quantity quote for renovation bids.
Check if leftover tiles from a previous project are enough for a new area.

Frequently Asked Questions

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Last updated: 2026-05-23 · Reviewed by Nham Vu