Square Footage Calculator
Rectangle / Square
Triangle
Circle
Total Square Footage: 0 sq. ft.
How is Square Footage Calculated?
Square footage is a measurement of area, typically used in real estate and home improvement to determine the size of a floor, wall, or ceiling. The basic principle involves multiplying two dimensions to find the total surface area in "squares."
Whether you are ordering hardwood flooring, painting a bedroom, or listing a home for sale, knowing how to calculate square footage accurately prevents overpaying for materials or underestimating a project's scope.
Standard Formulas for Area
| Shape | Formula | Logic |
|---|---|---|
| Rectangle/Square | Length × Width | The most common room shape. Multiply the two perpendicular sides. |
| Triangle | (Base × Height) / 2 | Used for gables or triangular corner sections. |
| Circle | π × Radius² | Useful for circular patios or custom architectural features. |
Step-by-Step: Measuring a Room
- Clear the Perimeter: Move furniture away from walls to get a straight line-of-sight for your measuring tape.
- Measure Length: Stretch your tape measure along the longest wall from one corner to the other. Record the measurement in feet.
- Measure Width: Measure the wall perpendicular to your first measurement.
- Handle Inches: If your measurement is 10 feet 6 inches, convert the inches to feet by dividing by 12 (6 / 12 = 0.5). Your measurement is 10.5 feet.
- Multiply: Multiply Length × Width to get your total square footage.
Calculating Oddly Shaped Rooms
Most rooms aren't perfect rectangles. They often have alcoves, closets, or L-shaped layouts. To calculate these accurately:
- Sectioning: Break the room down into smaller, manageable rectangles or triangles.
- Calculate Individually: Find the square footage for each individual section.
- Sum the Total: Add all the sections together to find the grand total for the space.
The "Waste Factor"
When purchasing materials like tile, laminate, or carpet, professionals recommend adding a 10% to 15% waste factor. This accounts for cuts, mistakes, and damaged pieces during installation. If your room is 100 sq. ft., you should buy enough material for 110 sq. ft. to ensure you don't run out mid-project.