Formula
How this estimate works
rectangle = length x width; triangle = base x height / 2; circle = pi x radius squared
A 12 ft by 10 ft room is 120 sq ft; add separate shapes for closets, offsets, or irregular areas.
How to calculate square footage
For a rectangle, multiply length by width. For a triangle, multiply base by height and divide by 2. For a circle, square the radius and multiply by pi.
Use square footage for material estimates
Square footage is the first step for paint, drywall, flooring, mulch, gravel, pavers, and many other home project estimates.
Assumptions used
- Each shape can be multiplied by quantity.
- Square yards are calculated by dividing square feet by 9.
- Square meters are converted from square feet for planning.
Before you order materials
- Break irregular spaces into simple shapes.
- Measure each room or section separately.
- Use the final square footage as the starting point for material calculators.
Frequently asked questions
How do I calculate an irregular room?
Break the room into rectangles, triangles, or circles, calculate each area, and add them together.
How many square feet are in a square yard?
One square yard equals 9 square feet. Use this conversion when flooring, turf, carpet, or fabric is priced by square yard instead of square foot.
Can I include multiple rooms?
Yes. Use the multi-area rows to add each room or project area.