How the tile calculator works
Tile is sold by the piece and shipped by the box, so the job is to turn your floor or wall into an area, work out how much space one tile actually occupies, and divide. The part that trips people up is the second step — a tile does not cover its own size, it covers its size plus half a grout joint on every side.
- Find the area. Length × width for a rectangle, or enter a total if you have already measured an awkward room.
- Add the grout joint to the tile. A 12 × 12 in tile with a 1/8 in joint occupies 12.125 × 12.125 in, which is 1.02 sq ft — not 1.00. This is the step most quick estimates skip.
- Choose a pattern and let it set the waste. Straight layouts waste least; anything cut on an angle wastes more.
- Add waste. The pattern gives you a starting figure; raise it for awkward rooms.
- Divide, then round up to whole tiles and whole boxes. You cannot buy part of either.
The calculator also works out the two consumables people forget at the checkout. Thinset mortar — the adhesive — is roughly one 50 lb bag per 55 square feet with a standard 1/4 × 3/8 in notched trowel. Grout depends on how much joint there is to fill, so the calculator works it out from your tile size and joint width rather than using one flat rate: about 0.10 lb per square foot for 12 × 12 tile with a 1/8 in joint, and closer to 0.30 lb per square foot for small formats like subway.
Worked example: a 6 × 8 ft bathroom floor
Here is a full calculation worked through line by line. The floor is 6 ft by 8 ft, tiled with 12 × 12 in ceramic, a 1/8 in grout joint, laid straight, with 10% waste. The tile comes 10 pieces to a box.
- Area. 6 × 8 = 48 sq ft.
- Tile plus joint. 12 + 0.125 = 12.125 in each way, so 12.125 × 12.125 ÷ 144 = 1.021 sq ft per tile.
- Add waste. 48 × 1.10 = 52.8 sq ft to buy.
- Divide. 52.8 ÷ 1.021 = 51.7, which rounds up to 52 tiles.
- Boxes. 52 ÷ 10 = 5.2, so 6 boxes — 60 tiles, with 8 left over for repairs.
The consumables follow from the 48 sq ft you actually set. Thinset: 48 ÷ 55 = 0.87, so one 50 lb bag. Grout: 48 × 0.104 = about 5 lb, which means a 10 lb bag is plenty and a 25 lb bag is more than you need for this room.
The same floor in 12 × 24 in tile
Larger tiles change the arithmetic in your favour twice over. Each 12 × 24 tile with a 1/8 in joint occupies 12.125 × 24.125 ÷ 144 = 2.031 sq ft, so 52.8 ÷ 2.031 = 26 tiles — half as many pieces to set. At 8 pieces per box you need 4 boxes. Better still, there is roughly 25% less joint to fill, so grout drops to about 3.7 lb. The trade-off is that big tiles are less forgiving of an uneven subfloor, and every cut piece is a bigger loss when it cracks.
The same floor in 3 × 6 in subway tile
Small tile is the opposite story. Each 3 × 6 subway with a 1/8 in joint occupies 3.125 × 6.125 ÷ 144 = 0.133 sq ft, so 52.8 ÷ 0.133 = 397 tiles — at 40 pieces per box, 10 boxes. The joint area is nearly three times that of the 12 × 12 layout, so grout jumps to roughly 14 lb, and you will spend an extra day setting and grouting. Subway looks superb on a wall and is a lot of work on a floor; know which one you are signing up for.
Where the answer moves
- Pattern. Switching the bathroom above to a 45° diagonal raises waste from 10% to 15%: 55.2 sq ft to buy, 55 tiles, still 6 boxes but with only 5 tiles of margin instead of 8. That margin is your entire buffer for a cracked piece, which is why diagonal jobs get away with less forgiveness.
- Joint width. Going from 1/8 in to 1/4 in on 12 × 12 tile takes each tile from 1.021 to 1.042 sq ft. Across a whole house that is about 2% more tile and noticeably more grout.
- Room shape. An L-shaped room, a fireplace hearth, or a run of built-in cabinetry pushes cutting up sharply. Add 5% on top of the pattern allowance for any of these.
- Walls versus floors. This calculator works for both — measure the wall area the same way, but remember to subtract window and door openings before you enter the figure, and use the total-area mode.
Change any of these and the tile count, boxes, thinset and grout all move together. The example is here to show where the numbers come from, not to replace measuring your own room.
Tile size reference
These are the formats most stocked in US stores, with the piece count and coverage you can typically expect in one box. Box quantities vary by manufacturer — always check the label before you order.
| Tile size | Area per piece | Typical pieces per box | Approx. sq ft per box |
|---|---|---|---|
| 3 × 6 in subway | 0.125 sq ft | 40 | 5 |
| 4 × 4 in | 0.11 sq ft | 44 | 4.9 |
| 6 × 6 in | 0.25 sq ft | 24 | 6 |
| 12 × 12 in | 1.00 sq ft | 10 | 10 |
| 12 × 12 in mosaic sheet | 1.00 sq ft | 10 | 10 |
| 6 × 24 in plank | 1.00 sq ft | 12 | 12 |
| 12 × 24 in | 2.00 sq ft | 8 | 16 |
| 18 × 18 in | 2.25 sq ft | 6 | 13.5 |
| 24 × 24 in | 4.00 sq ft | 4 | 16 |
Mosaic is worth a note: it comes as 12 × 12 in sheets of small tiles bonded to a mesh backing, so it handles curves and shower floors that rigid tile cannot. The joints between the little pieces are already set at the factory, which is why mosaic uses the narrowest joint of any format here.
Choosing a grout joint width
Joint width is partly structural and partly cosmetic. Narrow joints look modern and show off a rectified tile with crisp edges; wide joints forgive tiles that are not perfectly uniform.
| Joint width | Use it for | Worth knowing |
|---|---|---|
| 1/16 in | Mosaic, rectified porcelain, glass | The tightest practical joint. Needs dead-flat substrate and precisely sized tile |
| 1/8 in | Most interior ceramic and porcelain | The default. Wide enough to forgive minor size variation, narrow enough to look clean |
| 3/16 in | Handmade, zellige, rustic-look tile | Accommodates real variation in tile size and thickness |
| 1/4 in | Natural stone, slate, outdoor paving | Also gives movement joints room to breathe on exterior work |
Two rules that matter more than the width itself. Use sanded grout for joints 1/8 in and wider, and unsanded for anything narrower — unsanded grout shrinks less in a tight joint, and sanded grout will not pack into one. And always leave movement joints where tile meets a wall, a change of plane, or a structural joint, filled with flexible caulk rather than grout. Grout will crack there; caulk is supposed to flex.
What tile costs in 2026
Tile pricing spans an unusually wide range, because material and labour are almost independent decisions. These are the ranges most US homeowners are seeing in 2026.
| Material | Tile only (per sq ft) | Installed (per sq ft) | Best for |
|---|---|---|---|
| Ceramic | $1 – $5 | $5 – $13 | Interior walls, light-traffic floors, budget remodels |
| Porcelain | $3 – $10 | $7 – $20 | Bathrooms, kitchens, entryways — dense and near waterproof |
| Porcelain wood-look plank | $4 – $12 | $9 – $22 | Whole-house flooring that survives water and dogs |
| Natural stone | $5 – $15 | $12 – $30 | Feature floors and hearths; needs sealing |
| Glass or mosaic | $7 – $30 | $15 – $40 | Backsplashes, shower niches, accent bands |
For the bathroom in the example — 48 sq ft in mid-range ceramic at $3 per square foot — tile comes to about $145, which is 6 boxes at roughly $24 each. Setting materials add another $60 to $90: one bag of thinset at $15 to $25, a 10 lb bag of grout at $15 to $25, plus a notched trowel, spacers, a grout float and sealer if you do not already own them. Hiring the work out, expect $5 to $13 per square foot in labour, putting the same bathroom between roughly $240 and $620 for the installation, or $450 to $850 all in.
Four things move the total more than the price of the tile: subfloor preparation, because a floor that is not flat needs levelling compound or a new backer board before the first tile goes down; demolition and haul-away of the old floor; the pattern, since diagonal and herringbone layouts are routinely quoted at a premium for the extra cutting time; and your region, where labour rates vary by more than double between markets.
These are planning figures, not quotes. Prices shift with region, season and supplier, and whole-house orders are usually discounted. Use the calculator to get the quantities right, then price the job locally.
Pro tips
- Buy at least one extra box. Tile is batch-dyed, so a later box from a different lot may not match — and discontinued lines disappear fast. Keep the spare for repairs.
- Open a box before you start. Check for shade variation and damage, and confirm the pieces per box matches what you entered.
- Dry-lay a row first. Laying a row of loose tiles across the room shows you where the cuts land before any mortar is mixed.
- Mix thinset in small batches. It skins over in about 20 minutes in warm weather. Throw it out rather than re-tempering it with more water.
- Buy 10% more grout than you calculate. It goes further than you think during clean-up, and a second trip for a single bag is not worth it.
- Seal natural stone before grouting. Grout stains unsealed stone badly, and the haze is very hard to remove afterwards.
- Use the share link to save your measurements or send them to a supplier for a quote.