How this calculator works
This runs our tile calculator on your area. Each tile covers its own size plus a grout joint, so the tiles are the area plus waste divided by that. Thinset is the area divided by the coverage of a 50 lb bag with your trowel, grout comes from the volume of the joints, and cement board is sold in 3 × 5 ft sheets.
Worked example: a 5 × 8 ft floor (40 ft²) in 12 × 12 in tiles with 1/8 in joints and 10% waste takes 44 tiles (5 boxes of 10), 1 bag of thinset, 3.1 lb of grout and 3 sheets of cement board over a wood subfloor.
Materials by area (12 × 12 in tiles, 1/8 in joints, 10% waste)
Boxes of 10 tiles, 50 lb bags of thinset at 65 ft² a bag.
| Area | Tiles | Boxes | Thinset bags | Grout |
|---|---|---|---|---|
| 25 ft² | 27 | 3 | 1 | 2.0 lb |
| 40 ft² | 44 | 5 | 1 | 3.1 lb |
| 60 ft² | 65 | 7 | 1 | 4.7 lb |
| 80 ft² | 87 | 9 | 2 | 6.3 lb |
| 100 ft² | 108 | 11 | 2 | 7.8 lb |
Tips before you buy
- Buy all the tile from one lot. Color and size vary between lots, and tile is hard to match later.
- Do a dry layout before you spread any thinset, and shift the starting line so that the edge tiles are not thin slivers.
- Large-format tile needs a flatter floor, a bigger trowel and usually back-buttering, which uses more thinset.
- Take out the toilet and baseboards if the tile will run under them, and plan for the door to clear the new floor height.
- Let the thinset and grout cure for the time on the packaging before walking on the floor or using the shower.
Tools & materials for this project
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Frequently asked questions
How many tiles do I need for a 5x8 bathroom floor?
40 tiles of 12 × 12 inches cover the 40 ft² exactly, and 44 with 10% for cuts and breakage, which is 5 boxes of 10.
How much thinset and grout does a bathroom floor need?
About 1 bag of thinset (50 lb, with a 1/4 × 3/8 inch trowel) and roughly 3.1 lb of grout, so a 10 lb bag is enough for 12 × 12 inch tiles with 1/8 inch joints.
Do I need cement board under tile?
Over a wood subfloor, tile needs a stable base such as cement board or an uncoupling membrane. For this floor that is 3 sheets of 3 × 5 ft cement board. Check what your tile and thinset instructions require.
How many large tiles do I need for the same floor?
In 24 × 24 inch tiles with 3/16 inch joints and 15% waste: 12 tiles (3 boxes of 4) and 1 bag of thinset with a bigger trowel. Large tiles need a much flatter floor.
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Related calculators & guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.