How to measure
Measure the tiled face rather than the room footprint when working on walls, showers, or backsplashes. Separate niches, benches, borders, and different tile sizes so each product receives its own count.
Surfaces calculator
Tile Calculator
Estimate tiles by room and tile size, including grout joints and overage. Switch between US customary and metric units, adjust the assumptions, and keep every step visible.
ReviewedNovember 2, 2026
ScopeFormula, defaults & sources
Report an issue ↗The calculation
A visible formula, not a black box.
Tiles & boxes · Mathematical derivationtiles = (surface area + additional area) × waste factor ÷ individual tile area
Inputs are converted to a common base unit before calculation. Purchase quantities are rounded only at the final buying boundary.
Example inputDefaultStatus
Surface length12 ftReplace with measurement
Surface width10 ftReplace with measurement
Additional tiled area0 ft²Planning default — verify
Tile length12 inPlanning default — verify
Tile width12 inPlanning default — verify
Tiles per box12 Planning default — verify
Waste allowance12 %Planning default — verify
Worked example
Example: a 12 × 10 ft surface
For nominal 12 in tiles, 12 per box, and 12% allowance, the estimate rounds to 12 boxes. Layout and spare-stock needs may change this.
Use this to understand the workflow—not as a recommendation for your project.Sources & scope
What supports this calculation.
Industry guidanceCeramic Tile Education Foundation homeowner guide ↗
Layout, joints, size variation, and product data affect the installation plan.
Mathematical derivationNIST SI conversion factors ↗Exact length, area, and volume unit conversions; the project formula is derived from standard geometry.
Common mistakes
Check the job, not just the number.
- 01Leaving the example tile inputs unchanged instead of entering measured project values.
- 02Treating an editable coverage, size, density, or allowance as universal instead of checking the selected product label, project documents, and local requirements.
- 03Ordering from the rounded result without reviewing exclusions: The count is based on nominal tile dimensions. Pattern, orientation, calibration, breakage, and spare tiles for future repairs can change the appropriate allowance.
Questions, answered
Tile FAQ
What does the Tile Calculator estimate?
Estimate tiles by room and tile size, including grout joints and overage. The primary output is tiles & boxes, with the intermediate assumptions kept visible.
How is the tile result calculated?
The visible formula is: tiles = (surface area + additional area) × waste factor ÷ individual tile area. Inputs are converted to a common base unit before the final purchase boundary is rounded.
Are the default values recommendations?
No. Dimensions are worked examples and product-dependent presets are planning defaults. Replace them with the selected product label, project documents, and local requirements.
Is the result ready to order from?
Use it as a checked planning estimate, then confirm packaging, minimum orders, installation instructions, site conditions, and any code or professional-design requirements.
Project notes
Measure, adjust, and verify.
Details specific to tile planning.
What the result includes
The tool divides adjusted surface area by nominal tile face area, rounds up to individual tiles, then rounds again to the entered number of tiles per box.
When to adjust allowance
Increase overage for diagonal layouts, centered patterns, narrow edge cuts, fragile tile, shade variation, or spare stock. Multi-size modules should use the manufacturer's pattern coverage instead of a single-tile count.
Limitations
Grout joints, calibration, trim pieces, mosaics on sheets, mortar, membrane, backer board, and movement joints are separate. Nominal dimensions do not always equal installed module dimensions.