How do I measure a room for tile?

Measure the room's length and width in feet, then multiply them to get the square footage (length × width). For a floor that's 10 ft by 12 ft, that's 120 sq ft. Break odd shapes into rectangles, add the pieces together, subtract large openings, then add 10–15% for waste.

What tools do I need to measure for tile?

A 25 ft tape measure, a pen and paper or your phone for notes, and a calculator. A laser measure speeds up big or tall rooms but isn't required. Sketch the room first so you have a place to write each wall's length.

Do I measure the floor or the walls?

Measure whichever surface you're tiling. For floor tile, measure the floor's length and width. For wall tile or a shower, measure each wall's width and height and add them up. Many bathrooms need both floor and wall measurements.

Should I subtract doors and windows when measuring?

For walls, yes — subtract large openings like a window, door, or shower niche so you don't pay to tile empty space. For floors, only subtract permanent fixtures that sit on the floor, such as a kitchen island or a tub footprint; don't subtract small things like a toilet base.

How to Measure a Room for Tile (Step by Step)

Quick answer: Measure the room’s length and width in feet and multiply them for square footage (a 10 ft × 12 ft floor = 120 sq ft). Split odd shapes into rectangles and add the pieces. For walls, measure each wall’s width × height and subtract big openings. Finish by adding 10–15% waste, then convert to a tile and box count.

Getting the measurement right is the whole ballgame — every tile, grout, and cost estimate is built on it. The good news: it’s just multiplication once you have clean numbers. This guide covers the tools, the method for both floors and walls, irregular rooms, and a worked example. When you’re done, drop the numbers into the tile calculator for an exact count.

What you’ll need

A 25 ft tape measure (a laser measure helps in big or tall rooms).
Pen and paper or your phone to note each measurement.
A calculator — or let our tool do the math.
A quick sketch of the room so every wall has a place to write its length.

Measuring a floor (step by step)

Clear the space so you can reach each wall.
Measure the length (longest wall) in feet and inches. Take it in a couple of spots — old rooms aren’t perfectly square, so use the longer reading.
Measure the width the same way.
Convert inches to a decimal (e.g. 12 ft 6 in = 12.5 ft) and multiply: length × width = square feet.
Subtract only large floor fixtures, like a kitchen island or tub footprint. Skip small ones like a toilet base.

Irregular and L-shaped rooms

Don’t try to measure an odd shape in one go. Divide it into rectangles, measure each, and add the areas together.

Example — L-shaped room:
Main area 12 ft × 10 ft = 120 sq ft. The bump-out is 4 ft × 6 ft = 24 sq ft. Total = 120 + 24 = 144 sq ft. Add 10% waste → 158 sq ft to buy.

Measuring walls or a shower

Wall tile uses the same idea, one wall at a time:

Measure each wall’s width × height and add the walls together.
Subtract large openings — a window, a door, or a shower niche — so you don’t buy tile for empty space.
For a tiled wainscot or backsplash, measure only the height you’re actually tiling, not the whole wall.

For full walk-through examples, see our wall tile, shower tile, and backsplash guides.

Turn measurements into tiles

Once you have square footage, two short steps finish the job:

Add waste — about 10% for straight layouts, 15% for diagonal or patterned. See how much extra tile to buy.
Convert to a tile and box count — read how many tiles do I need and how many boxes of tile do I need.

Common measuring mistakes

Mixing units. Keep everything in feet (turn inches into decimals) before you multiply.
Measuring in one spot. Walls aren’t always parallel — check both ends and use the larger number.
Forgetting the second surface. Bathrooms usually need floor and wall measurements.
Over-subtracting on floors. Don’t deduct little fixtures; you’ll come up short.
Skipping waste. Always measured area plus 10–15%, never the bare number.

Frequently asked questions

How do I measure a room for tile?: Measure the room's length and width in feet, then multiply them to get the square footage (length × width). For a floor that's 10 ft by 12 ft, that's 120 sq ft. Break odd shapes into rectangles, add the pieces together, subtract large openings, then add 10–15% for waste.
What tools do I need to measure for tile?: A 25 ft tape measure, a pen and paper or your phone for notes, and a calculator. A laser measure speeds up big or tall rooms but isn't required. Sketch the room first so you have a place to write each wall's length.
Do I measure the floor or the walls?: Measure whichever surface you're tiling. For floor tile, measure the floor's length and width. For wall tile or a shower, measure each wall's width and height and add them up. Many bathrooms need both floor and wall measurements.
Should I subtract doors and windows when measuring?: For walls, yes — subtract large openings like a window, door, or shower niche so you don't pay to tile empty space. For floors, only subtract permanent fixtures that sit on the floor, such as a kitchen island or a tub footprint; don't subtract small things like a toilet base.

Got your numbers? Plug them into our free tile calculator to get an exact tile count, waste, and number of boxes — no math required. For the full method behind the square footage, see how to calculate square footage for tile.