Find the area of a room, plot or wall in square feet and instantly convert it to square metres, square yards, square inches and acres. Add a price per square foot to estimate flooring, carpet or construction cost.
Formula
Area = Length × Width
Make sure both measurements use the same unit. The calculator converts everything to feet first, so you can measure in inches, yards, metres or centimetres.
Area conversions
| From | To | Multiply by |
|---|---|---|
| Square feet | Square metres | 0.0929 |
| Square metres | Square feet | 10.764 |
| Square yards | Square feet | 9 |
| Acres | Square feet | 43,560 |
| Square feet | Square inches | 144 |
Irregular rooms
- L-shaped: split into two rectangles, calculate each, and add them.
- Triangles: ½ × base × height.
- Circles: π × radius².
Example
A 15 × 12 ft living room is 180 sq ft (16.72 m²). At $4.50 per sq ft for flooring, materials cost about $810 – add 10% for waste.
Worked examples
- Bedroom: 11 ft 6 in × 10 ft 3 in → 11.5 × 10.25 = 117.9 sq ft.
- Metric room: 4.2 m × 3.6 m = 15.12 m² = 162.8 sq ft.
- L-shaped living room: split into 14 × 12 ft (168 sq ft) and 8 × 6 ft (48 sq ft) → 216 sq ft.
- Triangle garden bed: base 10 ft, height 6 ft → ½ × 10 × 6 = 30 sq ft.
- Round patio: 12 ft diameter → π × 6² ≈ 113.1 sq ft.
Converting feet and inches
Turn inches into decimal feet by dividing by 12: 3 in = 0.25 ft, 6 in = 0.5 ft, 9 in = 0.75 ft. So 12 ft 9 in = 12.75 ft. Alternatively choose “inches” as the unit and enter everything in inches.
Square footage for common projects
| Project | What to measure | Typical extra |
|---|---|---|
| Flooring (laminate, hardwood) | Floor area | 5–10% |
| Carpet | Floor area (rolls are 12 ft wide) | 10–15% |
| Tile | Floor or wall area | 10–20% |
| Paint | Wall area | 10% |
| Sod or turf | Lawn area | 5% |
| Roofing | Roof area (pitch increases it) | 10–15% |
Price per square foot
Real-estate listings often quote price per square foot to compare homes: divide the price by the living area. A $420,000 home with 1,750 sq ft costs $240 per sq ft. Builders and contractors also quote this way, so enter a price per sq ft above to estimate project costs.
Measuring tips
- Use a laser measure for long rooms – it’s faster and more accurate than a tape.
- Measure twice and record each wall; rooms are rarely perfectly square.
- Include closets when buying flooring, but exclude fixed cabinets and islands.
Real-life scenarios
- New flooring: Tom’s living room is 18 × 14 ft = 252 sq ft. With 10% extra for cuts he buys 278 sq ft of laminate; at $3.20 per sq ft, materials cost about $890.
- Renting an apartment: Two listings at $1,800 a month – 750 sq ft and 900 sq ft – cost $2.40 and $2.00 per sq ft per month. The bigger flat is better value per foot.
- Garden sod: A 40 × 25 ft lawn is 1,000 sq ft. Sod rolls usually cover 10 sq ft each, so about 100 rolls plus 5% spare.
- Indian property listings: A 1,200 sq ft flat is 111.5 m² or 133.3 sq yd – useful when listings switch between units.
Carpet area, built-up area and super built-up area (India)
Indian property listings use three measures. Carpet area is the usable floor inside the walls. Built-up area adds wall thickness and balconies. Super built-up area adds a share of common areas such as lobbies and stairs, and can be 25–40% more than carpet area. Under RERA, developers must state carpet area, so compare prices on that basis.
Related calculators
- Tile calculator – tiles and boxes for a floor
- Paint calculator – gallons for walls and ceilings
- Concrete calculator – yards and bags for a slab
FAQs
How many square feet is a 10×12 room?
120 square feet (11.15 m²).
How do I convert square metres to square feet?
Multiply by 10.764. For example, 20 m² × 10.764 = 215.3 sq ft.
How do I measure a room?
Measure wall to wall at floor level along the longest straight lines. Round up to the nearest inch.
Does square footage of a house include walls?
Home listings usually quote finished, heated living area measured to the outside of exterior walls; methods vary by country and region.
Next step: work out paint with the paint calculator.