Measuring rooms for flooring
- Measure each room at its longest and widest points, wall to wall, including closets you'll floor.
- Split L-shaped and irregular rooms into rectangles. Run each one separately and add the boxes to your project list, or add the areas together and enter the total as length × 1 ft.
- Leave out areas under fixed cabinets and islands. Don't subtract areas under furniture.
- Note doorways and where the floor meets other flooring, because each needs a transition strip.
How boxes are calculated
Area = length × width. Area to buy = area × (1 + waste). Boxes = area to buy ÷ coverage per box (printed on the box, and it varies a lot between products), rounded up. With the defaults (15 × 12 ft, 10% waste, 20 ft² per box): 180 ft² becomes 198 ft², which is 10 boxes.
Choosing a waste percentage
Waste depends on the room shape, the layout and the product. Simple rectangular rooms with click-lock planks often need 5–10%. Rooms with many corners, closets or angled walls need more, and diagonal or herringbone layouts more again. Hardwood also has some boards culled for defects or colour. Manufacturer installation guides often state their own allowance, so use that when they do. Leftover boxes are useful for future repairs.
Boxes for common room sizes
| Room | Area | Boxes at 7% | Boxes at 10% | Boxes at 15% |
|---|---|---|---|---|
| 10 × 10 ft | 100 ft² | 6 | 6 | 6 |
| 10 × 12 ft | 120 ft² | 7 | 7 | 7 |
| 12 × 12 ft | 144 ft² | 8 | 8 | 9 |
| 12 × 14 ft | 168 ft² | 9 | 10 | 10 |
| 14 × 16 ft | 224 ft² | 12 | 13 | 13 |
| 16 × 20 ft | 320 ft² | 18 | 18 | 19 |
| Room | Area | Boxes at 7% | Boxes at 10% | Boxes at 15% |
|---|---|---|---|---|
| 3 × 3 m | 9 m² | 5 | 5 | 6 |
| 3 × 3.6 m | 10.8 m² | 6 | 6 | 7 |
| 3.6 × 3.6 m | 12.96 m² | 7 | 8 | 8 |
| 3.6 × 4.2 m | 15.12 m² | 9 | 9 | 9 |
| 4.2 × 4.8 m | 20.16 m² | 11 | 12 | 12 |
| 4.8 × 6 m | 28.8 m² | 16 | 16 | 17 |
Underlayment, trim and transitions
- Underlayment: laminate and some vinyl need a separate underlayment, while others have it pre-attached. The calculator reports the room area. Rolls list their coverage.
- Expansion gap and trim: floating floors and hardwood need a gap at the walls. NWFA guidelines describe ¾ in for solid hardwood, and laminate and vinyl makers specify their own. It's covered with baseboard or shoe moulding, so use the baseboard calculator.
- Transitions: count each doorway or change of floor. The perimeter figure helps you budget quarter-round or shoe.
- Moisture barrier over concrete slabs, if the product requires one.
Before installation
Wood and wood-based floors move with humidity. NWFA guidelines call for the building to be enclosed and the HVAC running under normal living conditions before the flooring is delivered, and for flooring and subfloor moisture to be within the manufacturer's limits. Many vinyl and laminate products also specify an acclimation period. Follow the instructions in the box, because they also govern the warranty.
Worked examples
Bedroom, 12 × 11 ft, laminate at 22.5 ft² per boxBedroom, 3.66 × 3.35 m, laminate at 2.09 m² per box
Room length 12 ft · Room width 11 ft · Coverage per box 22.5 ft² · Waste / overage 10 %Room length 3.66 m · Room width 3.35 m · Coverage per box 2.09 m² · Waste / overage 10 %
- Boxes to buy: 7
- Room area: 132 ft²Room area: 12.3 m²
- Area with waste: 145.2 ft²Area with waste: 13.5 m²
- Underlayment: 132 ft²Underlayment: 12.3 m²
Open living area, 24 × 18 ft, vinyl plank at 20 ft² per boxOpen living area, 7.32 × 5.49 m, vinyl plank at 1.86 m² per box
Room length 24 ft · Room width 18 ft · Coverage per box 20 ft² · Waste / overage 8 %Room length 7.32 m · Room width 5.49 m · Coverage per box 1.86 m² · Waste / overage 8 %
- Boxes to buy: 24
- Area with waste: 466.6 ft²Area with waste: 43.3 m²
- Transition / perimeter length: 84 ftTransition / perimeter length: 25.6 m
Hallway, 20 × 4 ft, engineered wood at 26 ft² per boxHallway, 6.1 × 1.22 m, engineered wood at 2.42 m² per box
Room length 20 ft · Room width 4 ft · Coverage per box 26 ft² · Waste / overage 12 %Room length 6.1 m · Room width 1.22 m · Coverage per box 2.42 m² · Waste / overage 12 %
- Boxes to buy: 4
- Area with waste: 89.6 ft²Area with waste: 8.3 m²
Choosing a flooring type
- Laminate: a click-lock floating floor with a printed wear layer. It's affordable and scratch-resistant. Water resistance varies by product, so check the rating for kitchens and baths.
- Luxury vinyl plank (LVP): floating or glue-down. Many products are marketed as waterproof, which makes them popular in basements, kitchens and bathrooms. It's softer underfoot than tile.
- Engineered hardwood: a real wood veneer over a plywood or composite core. It's more dimensionally stable than solid wood, can often float or be glued over concrete, and can be refinished a limited number of times depending on the veneer thickness.
- Solid hardwood: nailed to a wood subfloor. It can be sanded many times, but it's more sensitive to moisture and usually not recommended below grade.
All four are estimated the same way: area plus waste, divided by the coverage per box.
Common mistakes
- Buying boxes from different lots. Colour and gloss can vary. Check the lot numbers match.
- Measuring to the baseboard instead of the wall. If you're replacing baseboard too, measure wall to wall.
- Forgetting closets and hallways that will get the same floor.
- Skipping the expansion gap. Floating floors buckle if they're pinned at the edges.
- Not keeping spares. A box or two left over makes future repairs invisible.
Checked against
Each case below is re-run against the calculator by our automated test suite.
| Case | Our result | Checked against | Result |
|---|---|---|---|
| 15 × 12 ft room, 20 ft² boxes, 10% waste: boxes | 10 | Hand calculation | Match |
| Case | Our result | Checked against | Result |
|---|---|---|---|
| 4.57 × 3.66 m room, 1.86 m² boxes, 10% waste: boxes | 10 | Hand calculation | Match |
Frequently asked questions
How many boxes of flooring do I need for 200 square feet?
With 10% waste you need 220 ft², which is 11 boxes at 20 ft² per box.
Do I subtract closets?
Add closets in if you're flooring them. Only subtract fixed cabinets or islands.
How much extra flooring should I buy?
Usually 5–10% for simple rooms, and more for complex rooms and diagonal or herringbone layouts. Follow the manufacturer if it states a figure.
How do I calculate flooring for multiple rooms?
Run each room and use "Add to project", or add all the areas and enter the total as length with width 1 ft.
Sources & assumptions
The results are planning estimates, and the cost figures only use prices you enter. Product yields, densities and coverage rates vary, so check the label or ask your supplier, and follow local codes. Figures marked "approximate" or "rule of thumb" are general practice, not exact standards.
See how we calculate and test our formulas and the changelog. Last updated 2026-10-08.
Reviewed by the MaterialWhiz Editorial Team. This estimate uses the assumptions shown in the calculator. Review the result against your supplier's product coverage and site conditions. Last reviewed: October 10, 2026. See how we calculate · Report a correction.