Enter the bathroom length and width in feet, the coverage listed on one box of tile, and the waste percentage you want to use. The tool instantly shows the base square footage, the adjusted footage after waste, and the number of full boxes to buy. For irregular bathrooms, split the room or wall into smaller rectangles, calculate each area, and add the totals together before you compare quotes or place an order.
Bathroom Tile Calculator
Estimate square footage, total tile with waste, and how many boxes to buy.
**Quick waste presets**
Use 10% for a straight lay, 12% to 15% for diagonal or small bathrooms with many cuts, and more for complex patterns.
Base square footage**80.0 sq ft**
Square footage with waste**88.0 sq ft**
Boxes to buy**6 boxes**
Extra coverage after rounding**2.0 sq ft**How to Use the Bathroom Tile Calculator
- Measure the tile area. Use the longest points of the bathroom floor or wall in feet. If the room has a jog, shower alcove, or toilet nook, break it into smaller rectangles and add the square footage together.
- Enter the box coverage. Look at the tile carton or product page and use the coverage listed for one full box. This number varies a lot between mosaic sheets, large-format tile, and natural stone.
- Choose a waste percentage. Start with 10% for a straight layout. Increase the number for diagonal patterns, many cuts, or fragile materials that are more likely to chip during installation.
- Read the results. The calculator shows base square footage, square footage with waste, estimated boxes to buy, and likely extra coverage after rounding up to whole boxes.
Once you have these numbers, compare them with the manufacturer coverage on the exact tile you plan to install. Ordering based on the actual carton coverage is much more reliable than using a generic online average.
Bathroom Tile Waste Percentage Guide
Waste is the extra material you buy to cover cuts around toilets, vanities, corners, shower niches, and breakage during installation. A simple grid layout usually needs less waste than a diagonal or patterned installation.
| Layout or project type | Recommended waste | Why |
|---|---|---|
| Straight lay in a simple bathroom | 5% to 7% | Few cuts, minimal pattern matching, and a square room |
| Standard bathroom remodel | 10% | Safe default for most floors and many basic wall layouts |
| Diagonal layout or many obstacles | 12% to 15% | More edge cuts around corners, plumbing, and tight spaces |
| Herringbone, mosaic, or complex patterns | 15% to 20% | Higher chance of off-cuts, pattern waste, and breakage |
How Square Footage and Box Count Are Calculated
The math is simple once you break it into steps:
- Square footage: length x width
- Adjusted footage: square footage x (1 + waste percentage / 100)
- Box count: adjusted footage divided by coverage per box, rounded up to the next whole box
For example, an 8 ft by 10 ft bathroom has 80 square feet of base area. Add 10% waste and the working total becomes 88 square feet. If one box covers 15 square feet, you divide 88 by 15 and get 5.87, which means you should buy 6 boxes. You cannot buy 0.87 of a box, so the last step is always rounding up.
When to Measure Floors and Walls Separately
If you are tiling both the bathroom floor and the shower walls, calculate each surface separately instead of combining everything into one rough guess. Floors often use a different tile size, a different layout, or a different waste allowance than vertical wall tile. Separate measurements lead to cleaner orders and fewer leftover boxes.
Common Bathroom Tile Estimating Mistakes
- Ignoring obstacles: toilets, vanities, tubs, niches, and curb edges create extra cuts even when they reduce the open floor area.
- Using the wrong box coverage: always use the manufacturer coverage printed for the exact tile, not a generic number from another product.
- Choosing too little waste: 5% may work for a plain layout, but tight bathrooms and patterned designs usually need more material.
- Forgetting future repairs: keeping one extra box after the job makes later chip or crack repairs much easier.
- Skipping separate room sections: L-shaped bathrooms and shower bump-outs should be measured as smaller rectangles and then added together.
A tile estimate is still a planning number, not a substitute for careful field measurement. Before ordering expensive material, double-check dimensions, confirm the pattern with your installer, and verify the final box coverage on the product page or carton.
FAQ
How much waste should I add for bathroom tile?
For a simple straight lay in a standard bathroom, 10% waste is a safe default. Use 5% to 7% only when the room is very square and the tile is easy to cut. Move closer to 12% to 18% for diagonal layouts, patterned installs, shower niches, or rooms with many corners and obstacles.
Do I subtract the bathtub or vanity area from the square footage?
You can subtract large fixed areas that definitely will not receive tile, but do not overdo it. Small bathrooms still create a lot of cutting around fixtures, so many homeowners keep the subtraction conservative and rely on the waste percentage to cover the real-world cuts.
Why does the calculator round up the number of boxes?
Tile is sold by the box, not by exact square foot. If your adjusted total needs 5.2 boxes, you still need 6 full boxes to finish the job. Rounding up also gives you a small buffer for breakage, bad cuts, and future repairs with matching tile.