Flooring Calculator
To find how much flooring you need, multiply the room length by width for the area, then add 5–15% for waste and cuts. Divide by the coverage per box to get the number of boxes. A 15×12 ft room needs about 198 sq ft with 10% waste, costing roughly $600–$2,000 installed depending on material.
- Standard waste
- 10%
- Typical box
- ~20 ft²
- Buy
- Full boxes
Your measurements
Check the flooring carton — often 18–24 ft².
Enter your measurements
Fill in the fields to see your estimate.
The formula
Flooring (ft²) = Length × Width × (1 + waste %); Boxes = area ÷ coverage per boxHow to calculate it manually
- 1
Measure the room
Multiply length × width. Split L-shaped rooms into rectangles and add them.
- 2
Add a waste factor
5% for straight lay, 10% standard, 15% for diagonal or patterned layouts.
- 3
Divide by box coverage
Check the carton — most boxes cover 18–24 sq ft.
- 4
Round up
Always round boxes up and keep a spare for future repairs.
Example calculation
A 15 ft × 12 ft room: 180 ft² × 1.10 = 198 ft². At 20 ft² per box that's 10 boxes.
Flooring cost by material
Installed cost per square foot, including materials and labor.
| Material | Cost per ft² (installed) | Lifespan | Best for |
|---|---|---|---|
| Laminate | $2 – $6 | 15–25 yrs | Budget, DIY |
| Luxury vinyl plank | $3 – $7 | 20–25 yrs | Moisture-prone rooms |
| Engineered wood | $5 – $10 | 25–30 yrs | Wood look, stability |
| Solid hardwood | $6 – $15 | 30–100 yrs | Long-term value |
Common flooring estimating mistakes
Forgetting the waste factor
Cuts at walls and around obstacles waste material. Add 10% for straight lay and 15% for diagonal or herringbone.
Measuring an L-shaped room as one rectangle
Split irregular rooms into rectangles, calculate each, and add them before applying waste.
Not buying a spare box
Dye lots change between runs. Keep an extra box sealed for future repairs so it matches.
Ignoring underlayment and transitions
Underlayment, trim, and transition strips add to the budget and aren't in the flooring square footage.
Frequently asked questions
Related guides
Related calculators
Ready to start your flooring project?
Run the numbers above, then explore related tools and guides to plan every step.