How to Measure a Room for Flooring, Paint and Tile
Almost every material you buy for a room comes from the same few measurements. Get them right once and you can work out flooring, paint and tile without going back to the tape measure. This guide shows how to measure, what to subtract, and how much extra to add.
What you need
- A 25-foot tape measure
- A notepad or phone note to sketch the room and write down each measurement
- A helper for long walls, so the tape stays straight
Step 1: Measure the floor
Measure the length and width of the room from wall to wall at the widest points. Write the numbers in feet and inches, then convert to decimal feet before you multiply. For example, 13 feet 6 inches is 13.5 feet, not 13.6. Multiply length by width to get square feet.
Step 2: Split odd shapes into rectangles
For an L-shaped room, split the floor into two rectangles, measure each one, and add the areas. Include closets and alcoves if they get the same flooring.
| Section | Size | Area |
|---|---|---|
| Main room | 12 × 14 ft | 168 sq ft |
| Alcove | 6 × 8 ft | 48 sq ft |
| Total | 216 sq ft |
If the flooring will not run under cabinets or a kitchen island, measure those and subtract them.
Step 3: Measure the walls for paint
Measure the distance around the room and multiply by the ceiling height to get total wall area. Then subtract the openings you won't paint: about 20 square feet for a standard door and 15 for a window. A 12×12 foot room with 8-foot ceilings, one door and two windows works out to 384 − 20 − 30 = 334 square feet of wall.
Triangular gable walls are half the base times the height. Paint the ceiling separately by multiplying its length and width.
Step 4: Add a waste allowance
Cuts, mistakes and future repairs all use material. These are typical allowances, but your product's instructions come first.
| Material | Typical extra |
|---|---|
| Laminate or vinyl plank | 5–10% |
| Hardwood | About 10% |
| Tile, straight layout | About 10% |
| Tile, diagonal or large format | About 15% |
| Paint | Round up to the next gallon |
Step 5: Turn measurements into a shopping list
Flooring is sold in boxes, so divide your area plus waste by the coverage of one box and round up. For the 216 square foot floor above with 10% waste, that is 237.6 square feet, or 12 boxes of 20 square feet. Paint is bought in gallons, and tile by the piece. Our flooring calculator, paint calculator and tile calculator do this math for you.
Common measuring mistakes
- Forgetting closets, hallways or doorway thresholds
- Mixing inches and feet when multiplying
- Rounding down instead of up
- Using one ceiling height for a room with a vaulted or sloped ceiling
- Buying everything at the last minute, when a box from a different batch can look slightly different
Measure twice, add your waste allowance, and buy all of one material at the same time. That keeps the color consistent and leaves you a few spares for repairs later.
Enter your room size, waste allowance and price to see how many boxes of flooring you need and what the material costs.
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