Tile Calculator: How Many Tiles and Boxes You Need

How to work it out

Measure the floor or wall. For an L-shaped room, add two rectangles.
Enter the tile size from the box or product page.
Choose the extra to allow. 10% is a common starting point for a straight layout, and diagonal or herringbone patterns need more.
Enter how much one box covers, also printed on the box, to see how many boxes to buy.

How much extra to allow

Layout	Common extra
Straight layout, simple room	About 10%
Diagonal or herringbone	About 15% or more
Large tiles or lots of cuts	15% or more

These are common starting points. Your site, climate and supplier may call for something different.

Keep a few spares

Tiles from a later batch can differ slightly in colour. Keeping a few spare tiles from the same batch makes future repairs easier to match.

What this calculator leaves out

It counts tiles and boxes only. Grout, adhesive or mortar, edging and backer board are bought separately, so check their coverage on the bag or box.

Common questions

How many tiles do I need for 100 sq ft?

With 12 by 12 inch tiles, each tile covers 1 sq ft, so 100 tiles plus extra, about 110 with 10% extra. With 12 by 24 inch tiles, each covers 2 sq ft, so about 55.

How do I work out tiles for a wall?

Measure the width and height of each wall as rectangles, and leave out doors and windows by measuring around them. The maths is the same as for a floor.

How much extra tile should I buy?

About 10% for a straight layout and about 15% for diagonal or herringbone patterns, or when there are lots of cuts. Your installer may suggest a different figure for your room.

Doing this job for a customer? Turn your numbers into a free written estimate on QuoteToPaid.

Tile calculator