About the Tile Calculator
A tile calculator works out how many tiles a floor or wall needs, based on the area and the tile size, with a waste allowance. Ordering tile accurately matters more than most materials because dye lots vary between production batches.
The formula
Tiles = area / tile area, plus waste percentageTile dimensions in inches are converted to square feet by dividing by 144. The waste factor covers cuts at edges, breakages, and future repairs.
How to use this calculator
- 1Enter your Room/Area Length (ft). The field starts at
12, which you can overwrite. - 2Enter your Room/Area Width (ft). The field starts at
10, which you can overwrite. - 3Enter your Tile Length (inches). The field starts at
12, which you can overwrite. - 4Enter your Tile Width (inches). The field starts at
12, which you can overwrite. - 5Enter your Waste % (5–10%). The field starts at
10, which you can overwrite. - 6Read the result straight away — it recalculates as you type, so there is no button to press. Use Share to copy a link that reopens the page with your exact numbers filled in.
Worked example
| Input | Value |
|---|---|
| Room/Area Length (ft) | 12 |
| Room/Area Width (ft) | 10 |
| Tile Length (inches) | 12 |
| Tile Width (inches) | 12 |
| Waste % (5–10%) | 10 |
Result
Room Area: 120 sq ft
Tile Area: 1.0000 sq ft
Tiles Needed: 120
With 10% Waste: 132 tiles
Estimated Boxes (12/box): 11 boxes
Those are the values the page loads with, so you can reproduce this result yourself and then change one field at a time to see what drives the outcome.
Understanding your result
The waste percentage depends on layout more than on skill. A straight grid in a rectangular room wastes little — 5 percent is usually enough. A diagonal layout means cutting nearly every perimeter tile, pushing waste to 15 percent or more, and patterns requiring alignment such as herringbone waste more still.
Dye lot variation is the reason to over-order rather than reorder. Tiles from different production batches differ subtly in shade, and the difference is obvious when laid side by side. Buying enough at once, plus a box for future repairs, avoids a mismatch that can only be fixed by relaying the floor.
Things worth knowing
- Order 10 percent extra for straight layouts and 15 to 20 percent for diagonal or patterned ones.
- Keep a spare box after the job. Dye lots change, so a matching replacement may be unobtainable later.
- Grout lines add up: a 12-inch tile with 1/4-inch grout occupies 12.25 inches of run.
- Large-format tiles need a flatter substrate, since they cannot flex over irregularities.
- Check that all boxes carry the same batch or dye lot number before starting.
Frequently asked questions
How many tiles do I need?+
Divide the area to be tiled by the area of one tile, then add 10 percent for waste. A 120 square foot floor with 12-inch tiles needs 120 tiles plus 12 spare.
How much extra should I order?+
10 percent for straight layouts, 15 to 20 percent for diagonal or patterned ones. Buy an extra box beyond that for future repairs, since dye lots change between batches.
Do grout lines affect how many tiles I need?+
Slightly — they increase the effective size of each tile, so marginally fewer are needed. The effect is small enough that it is usually absorbed by the waste allowance.
Why should I keep spare tiles?+
Because production batches vary in shade. If a tile cracks two years later, a replacement from a new batch will not match, and the only fix would be relaying a section.