Flooring Sqft Calculator
Enter your room area, a waste percentage and the coverage per box to find exactly how much flooring to order.
To calculate flooring square footage, measure the room area and add 10% for waste. A 300 sq ft room needs 300 × 1.10 = 330 square feet of flooring. Divide that by the coverage per box — at 20 sq ft per box, you need 17 boxes.
Boxes are always rounded up — you cannot buy a partial box.
How much waste to allow
Waste is not optional. Every cut at a wall, doorway or corner produces an offcut, and boards get damaged during installation.
- 10% — simple rectangular rooms, straight-lay planks or standard tile
- 15% — diagonal layouts, herringbone, or rooms with lots of corners and alcoves
- 20% — large-format tile, busy patterns needing alignment, or very irregular rooms
Buy the extra in the same order. Flooring is made in dye lots, and a later top-up order can be a visibly different shade.
Working out boxes
Flooring is sold by the box, with coverage printed on the packaging — commonly 18 to 24 sq ft for laminate and engineered wood.
Divide your total including waste by the coverage per box, then always round up. For 330 sq ft at 22.5 sq ft per box: 330 ÷ 22.5 = 14.7, so order 15 boxes.
Keep one spare box after the job for future repairs — it is far cheaper than trying to match a discontinued product later.
Notes by flooring type
- Hardwood and laminate — sold by the box; some suppliers also quote linear feet, in which case use the linear feet calculator.
- Tile — check whether the price is per tile or per square foot. Large-format tile needs a bigger waste allowance.
- Carpet — comes on 12 ft wide rolls, so the practical purchase depends on how the roll cuts into your room; you often pay for more than your bare area. Frequently priced by the square yard.
- Vinyl and LVP — usually by the box, similar to laminate.
Flooring needed with waste
| Room area | +10% waste | +15% waste | Boxes at 20 ft²/box (10%) |
|---|---|---|---|
| 100 sq ft | 110 sq ft | 115 sq ft | 6 boxes |
| 200 sq ft | 220 sq ft | 230 sq ft | 11 boxes |
| 300 sq ft | 330 sq ft | 345 sq ft | 17 boxes |
| 500 sq ft | 550 sq ft | 575 sq ft | 28 boxes |
| 800 sq ft | 880 sq ft | 920 sq ft | 44 boxes |
| 1,200 sq ft | 1,320 sq ft | 1,380 sq ft | 66 boxes |
Frequently asked questions
How much extra flooring should I buy?
Add 10% for a simple rectangular room with a straight lay, 15% for diagonal or herringbone patterns and rooms with many corners, and up to 20% for large-format tile.
How do I calculate how many boxes of flooring I need?
Divide your total square footage including waste by the coverage per box printed on the packaging, then round up. 330 sq ft at 22.5 sq ft per box means 15 boxes.
Should I include closets in the flooring measurement?
Yes, if you are laying flooring in them. Measure each closet as a small rectangle and add it to the room total.
Why should I order all the flooring at once?
Flooring is manufactured in dye lots and colour varies slightly between batches. A top-up order placed later can be a visibly different shade from the original.
How do I measure a room for carpet?
Measure the length and width at the widest points and multiply. Because carpet comes on 12 ft wide rolls, ask your supplier to work out the actual cut — you may need to pay for more than your bare square footage depending on how the roll fits the room.