Calculate your quantities
Enter your measurements below. Change the example allowance, product information and price to match your project.
Enter measurements and select Calculate.
Prices use your chosen currency. A zero price leaves cost at zero. Material estimates exclude labor, tax, delivery and accessories. Enter decimal feet, not feet-and-inches notation. Decimal point or comma accepted; omit thousands separators.
How to use this square footage calculator
Split an L-shaped room into two non-overlapping rectangles. Enter decimal feet: 10 ft 6 in = 10.5 ft, not 10.6. This is a measured area estimate, not a legal or appraisal definition of living area.
- Measure the relevant area or volume using the units shown beside each input.
- Replace example product values with the supplier's yield, coverage, density or pack quantity where applicable.
- Set the extra allowance explicitly. Enter zero when you want the geometric quantity without an allowance.
- Select Calculate, then compare the unrounded purchasing basis with whole bags, boxes or packs where displayed.
Formula
Net ft² = first length × width + second length × width − deductions. Material area = net area × (1 + extra / 100). m² = ft² × 0.09290304.
Worked example
A 10 × 10 ft room plus an 8 × 5 ft alcove totals 140 ft². Subtract 10 ft² for an excluded area to get 130 ft²; adding 10% yields 143 ft² of material.
Six calculated examples
Only the first length changes in this table. All other inputs use the calculator's reset values shown above. These are mathematical scenarios, not measured supplier quotes.
| First length | Calculated quantities |
|---|---|
| 5 ft | Net area (ft²): 50; Net area (m²): 4.645; Material area (ft²): 55 |
| 8 ft | Net area (ft²): 80; Net area (m²): 7.432; Material area (ft²): 88 |
| 10 ft | Net area (ft²): 100; Net area (m²): 9.29; Material area (ft²): 110 |
| 12 ft | Net area (ft²): 120; Net area (m²): 11.148; Material area (ft²): 132 |
| 15 ft | Net area (ft²): 150; Net area (m²): 13.935; Material area (ft²): 165 |
| 20 ft | Net area (ft²): 200; Net area (m²): 18.581; Material area (ft²): 220 |
Frequently asked questions
Can I add more rooms?
Calculate groups separately and add their net areas. Avoid overlapping rectangles.
Are square feet and feet interchangeable?
No. Feet measure length; square feet measure area.
Does extra material increase my room area?
No. Net area stays unchanged; the allowance changes only estimated material quantity.
Units and calculation limits
One foot is 0.3048 meters; one cubic yard is 27 cubic feet. Calculations retain precision until display; whole-package quantities are rounded up. Outputs estimate quantities from your measurements and assumptions. Confirm product coverage and units before ordering.
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\nNeed length instead of area? Use the Linear Feet Calculator to convert square footage using a known material width, add waste and round up to stock lengths.
Ceiling project? Use the Ceiling Tile Calculator for rows, columns, orientation, full cartons and cost.