Tile Calculator for Floors & Walls
Figure out exactly how many tiles and boxes you need before you buy. Enter your measurements below and get a precise count — wastage, box rounding, and the full math included.
Calculate Your Tiles
10% for straight layouts; 15% for diagonal or herringbone patterns.
Check the box label — this varies by brand and tile size.
Why Getting the Tile Count Right Matters
Ordering tile is one of those deceptively simple parts of a renovation. You measure the room, divide by the tile size, and buy that many tiles — except that almost never works out in practice. Tiles break. Cuts along walls waste half a tile at a time. Corners, doorways, and outlets swallow whole pieces you never counted. And when you run short mid-project, the replacement batch can arrive a shade off from the first, a difference you will notice every single day. That is why every experienced tiler orders extra, and why a calculator that bakes wastage into the math matters far more than a rough guess.
Start by measuring carefully. For floors, measure the length and width of the room at the longest points, and do not subtract permanent fixtures like a bathtub or a kitchen island — the partial tiles cut around them still come out of full tiles. For walls and backsplashes, measure each section separately and add the areas together. Always work in consistent units — mixing feet and inches is the most common measuring mistake.
Tile size changes the calculation more than most people expect. Large-format tiles cover ground quickly and mean fewer grout lines, but they also produce more waste around obstacles because every cut sacrifices a bigger piece. Small tiles and mosaics waste less per cut but take far longer to set. A standard 10 percent wastage allowance covers most straightforward floor and wall jobs; raise it to 15 percent for diagonal layouts, herringbone patterns, or rooms with lots of corners, niches, and window openings.
Finally, tiles are sold by the box, and you cannot buy half a box. This calculator rounds your total up to whole boxes so you leave the store with enough material, not almost enough. It is also worth keeping one or two leftover boxes after the job is done. If a tile ever cracks years later, having a matching spare on hand beats hunting for a discontinued shade or living with a patch that does not quite match.
How to Use This Calculator
- Measure the area. For a floor, measure the room’s length and width in feet at the longest points. For walls or a backsplash, measure each section in feet and add them up, then enter the totals.
- Enter your tile size. Check the tile label and enter the length and width in inches — for example, 12 by 12 for standard floor tiles or 3 by 6 for subway tile.
- Set your wastage percentage. Leave the default 10% for straight grid layouts, or raise it to 15% for diagonal, herringbone, or cut-heavy jobs.
- Enter tiles per box. This is printed on the box or product listing. It varies widely, so do not guess — check the label.
- Click Calculate. You will see your net area, each tile’s area, the exact tile count with wastage, and the number of whole boxes to buy, plus a step-by-step math breakdown.
- Buy the boxes shown — and keep spares. Store one or two leftover boxes for future repairs; dye lots change and old tiles get discontinued.
Frequently Asked Questions
How much extra tile should I order for waste?
For most straight floor and wall layouts, 10% is the industry-standard allowance and covers cuts, breakage, and small mistakes. Raise it to 15% for diagonal layouts, herringbone, or rooms with many corners, niches, and fixtures. Very intricate mosaic or patterned work can justify 20%.
Do I need to account for grout lines in the calculation?
For estimating purposes, no. Grout lines are narrow enough that they barely change the tile count for a shopping list. The wastage percentage you add absorbs far more variation than grout spacing ever will. Just set your tiles with consistent spacers and the math holds.
Can I use this calculator for walls and backsplashes too?
Yes. Measure each wall or backsplash section in feet, multiply length by width for each, add the sections together, and enter the total as your area. The math is identical — only the surface changes. For a backsplash, remember to include the area behind the stove or under cabinets if tile runs there.
What if my room is not a perfect rectangle?
Break L-shaped or irregular rooms into rectangles, calculate each rectangle’s area (length × width), and add them together. Enter that total as your area. For angled walls, measure to the longest points — the wastage allowance will cover the extra cuts.
Should I keep spare tiles after the job is finished?
Absolutely. Keep at least one full box, stored flat in a dry place. Tiles get discontinued, dye lots shift between production runs, and a cracked tile five years from now is a quick fix only if you have a matching piece. Note the brand, color name, and batch number on the box before you store it.
A Confident Start to Your Tiling Project
Accurate numbers take the stress out of buying tile: no mid-project store runs, no pallets of leftover boxes, and no mismatched batches. Once your quantities are settled, the fun part begins — choosing grout color, laying out patterns, and watching the room transform. If you are planning the wider room around your new tile, explore our related decor guides on the blog for flooring pairings, paint colors that complement popular tile shades, and budget-friendly ways to finish the space.