What is a square footage calculator?
A square footage calculator computes the total area of a space from your length and width measurements, returning results in sq ft, square meters, or square yards. It handles common shapes — rectangle, circle, triangle, trapezoid, and composite layouts — and converts between units automatically so you can work in whatever you measured.
Use it to calculate square footage for flooring projects, tile orders, paint coverage, landscaping, or real estate listings. Enter your dimensions, add a waste percentage, and get an instant material and cost estimate alongside your area calculation.
How to calculate square footage
The process of calculating area depends on the shape of the space. Here is how each one works.
| Shape | Formula | Inputs needed |
|---|---|---|
| Rectangle / square | Length × width | Length and width in feet or meters |
| Circle | π × radius² | Diameter or radius |
| Triangle | 0.5 × base × height | Base length and height |
| Trapezoid | 0.5 × (a + b) × height | Both parallel sides and height |
| L-shape / composite | Split into rectangles, calculate area of each section, add them together | Dimensions of each section separately |
- 1
Measure the space
Use a tape measure to record the length and width in feet or inches. For a rectangular room, measure one wall for length and the adjacent wall for width.
- 2
Choose shape and units
Select the shape that matches your floor plan. Choose feet, inches, meters, or centimeters — the calculator converts to square feet and square meters automatically.
- 3
Enter dimensions and waste percentage
Enter your length and width in feet or your chosen unit. Add a waste allowance: 5 to 10 percent for hardwood flooring and laminate flooring, 10 to 15 percent for tile.
- 4
Review area and cost estimate
The calculator returns total square footage, adjusted material needs, and an optional project cost if you enter a price per square foot. Use this to compare suppliers or build a shopping list.
Common use cases
Installing flooring
Calculate the total square footage of a room to find out how many boards or tiles you need. Add waste for cuts. Works for hardwood flooring, laminate flooring, tile, and vinyl — any flooring material sold by the square foot or sq ft per box.
Paint and wall coverage
Multiply the length and width of each wall to get the surface area, subtract doors and windows, then divide by your paint's coverage rate per square foot. The calculator handles the multiplication so you only need to enter dimensions.
Real estate and property
Calculate the square footage of a room or an entire floor plan for listings, comparisons, or renovation planning. Consistent measurement methodology matters — always measure at floor level along interior walls.
Landscaping and outdoor areas
Determine sod, mulch, or gravel coverage for a yard or garden bed. Enter the area in square feet and convert to square yards if your supplier prices by the yard. The free square footage calculator handles the unit switch automatically.
Measurement tips
Measure at floor level
Always measure the length and width of the space at floor level along the baseboard. Walls are rarely perfectly parallel — take two measurements per wall and use the larger figure.
Split irregular rooms into sections
For an L-shape or any irregular shape, divide the floor into rectangles. Calculate the area of each section separately and add them together for the total square footage of the room.
Use consistent units
Do not mix feet and inches in the same calculation without converting first. If you measure the width of the space in feet, enter length in feet too. Use the unit selector to switch — the calculator handles the rest.
Always add waste
Never order flooring material to the exact number of square feet. Cuts, breakage, and pattern matching all consume extra material. A flooring project without a waste buffer almost always runs short.
Frequently asked questions
How do I calculate the square footage of a room?
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Simply measure the length and width in feet, then multiply the two figures together. A rectangular room that is 12 feet by 10 feet has 120 sq ft of floor area. For rooms that are not a perfect square or rectangle, split the floor into sections and add the area of each section together.
How do I calculate square footage for an irregular shape?
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Divide the space into regular shapes — rectangles, triangles, or trapezoids. Calculate the area in square feet for each section separately, then add them together for the total. The calculator supports composite shapes so you can enter each section and add them together in one session.
How much extra should I add for flooring waste?
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For hardwood flooring and laminate flooring, add 5 to 10 percent. For tile, add 10 to 15 percent to account for diagonal cuts and breakage. Enter the waste percentage into the calculator and it adjusts your material needs automatically.
Can I use this to calculate flooring in square yards?
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Yes. After you find the area in square feet, the calculator converts to square yards and square meters. Divide the total number of square feet by 9 to get square yardage manually, or use the unit selector to switch outputs.
What geometric shapes does the calculator support?
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Rectangle, square, circle, triangle, trapezoid, and L-shape or composite layouts. For each shape the calculator applies the correct geometric formula so you get an accurate area without doing the math yourself.