Tile Calculator

Tiles are sold in boxes, laid with cuts at every edge, and notorious for shade differences between batches — so ordering the exact floor area is how people end up with a mismatched strip along one wall. This calculator gives both numbers: how many tiles cover the bare floor, and how many to actually buy once cuts and breakage are allowed for.

How to use it

1. Enter the room dimensions in feet and the tile size in millimetres.
2. Set a wastage allowance — 10% for a straight layout, 15% for diagonal.
3. Buy the higher figure, and keep the spares.

Examples

• A 12 x 10 room in 600 x 600 mm tiles: 31 tiles cover it exactly, 35 with 10% wastage.
• The same room in 300 x 300 mm tiles needs four times as many, and usually more wastage.

Frequently asked questions

How many tiles do I need for a room?

Divide the floor area by the area of one tile, then add wastage. A 600 by 600 mm tile is about 3.88 sq ft, so a 120 sq ft room needs 31 tiles bare and about 35 with a normal allowance. This calculator does both, because the difference between them is what people forget to buy.

How much wastage should I allow?

Ten per cent for a straightforward rectangular room laid square. Fifteen for a diagonal layout, a room with many corners or alcoves, or a patterned tile that must be aligned. Larger tiles waste more per cut, because each cut discards a bigger piece.

How many tiles come in a box?

It depends on size: 600 by 600 mm tiles are usually four to a box, 300 by 300 mm often ten or more. Shops sell whole boxes, so round your total up to the next full box — the calculator gives you the tile count to convert.

Why should I buy spare tiles?

Because tile shade varies between production batches, sometimes visibly. If a tile cracks in two years and the batch is gone, the replacement will not match. Keeping four or five spares from the same batch is the cheapest insurance in the whole job.