Square Footage Calculator: Any Shape, Any Room
Enter dimensions in feet, inches, yards, meters, or centimeters. Get instant area in sq ft, sq m, sq yd, and acres with optional waste factor and cost estimate.
Last updated:Prefer a rectangle-only version with less copy? Use the fast SqFt calculator for the quickest room-size lookup. For the theory behind the formulas, see the guides hub — it covers price per sq ft, linear vs square, cubic vs square, and feet-and-inches measurement.
Tip: If you only have the diameter, divide by 2 to get the radius.
L-shape = two rectangles sharing a corner.
Add one row per rectangle and we'll sum them.
How to Use the Square Footage Calculator
- Pick a shape. Use rectangle, square, circle, triangle, trapezoid, L-shape, or irregular room depending on the layout you need to measure.
- Enter dimensions in any supported unit. Every field accepts feet, inches, yards, meters, or centimeters and converts before calculation.
- Read the result instantly. The tool shows square feet first, then square meters, square yards, acres, and square inches.
- Add waste or price if needed. This is useful for flooring, tile, carpet, and renovation budgeting.
Square Footage Formulas for Every Shape
Square footage is an area measurement. If your measurements are not already in feet, the calculator converts them first and then applies the formula for the selected shape.
| Shape | Formula | Example |
|---|---|---|
| Rectangle | Length × Width | 12 ft × 10 ft = 120 sq ft |
| Square | Side × Side | 10 ft × 10 ft = 100 sq ft |
| Circle | pi × r² | pi × 6² = 113.10 sq ft |
| Triangle | (Base × Height) / 2 | (14 × 9) / 2 = 63 sq ft |
| Trapezoid | ((a + b) / 2) × h | ((8 + 14) / 2) × 6 = 66 sq ft |
| L-Shape | (L1 × W1) + (L2 × W2) | (16 × 8) + (8 × 6) = 176 sq ft |
| Irregular | Sum of rectangles | (12 × 10) + (8 × 6) = 168 sq ft |
Why the Waste Factor Matters
When you are buying flooring, tile, carpet, or similar materials, the raw square footage is not always enough. Installers usually add 5% to 15% extra for cuts, breakage, pattern matching, and future repairs. This calculator lets you preview that total before you order.
Popular Use Cases
Flooring Calculator
Estimate hardwood, vinyl, or laminate with waste and pricing.
▤Tile Calculator
Estimate tile counts and box quantities for floors and walls.
▩Carpet Calculator
Square yards, 10% waste, and padding cost in one view.
⌂House Square Footage
Add up multiple finished spaces for whole-home totals.
$Cost per Sq Ft
Convert between total price and area-based budget numbers.
⟟Paint Calculator
Gallons needed at 350 sq ft per gallon for one or two coats.
⇄Sq Ft to Sq M
Quick unit conversion for international projects and listings.
+Multi-Room Total
Sum multiple rectangles when the same flooring covers several rooms.
10x12Room Size Examples
See square footage for 60+ common dimensions from 8x8 to 50x100.
Measurement Tips for Accurate Results
- Measure at floor level, not wall level. Walls are often not plumb, and the lowest point of the wall defines usable floor space.
- Run the tape wall to wall. Do not include baseboards in the reading; they sit on top of the finished floor.
- Measure in two directions. If the two lengths disagree by more than about 1 inch, average them — rooms are rarely perfect rectangles.
- Account for closets and alcoves. Use the L-shape or irregular tabs instead of guessing.
- Write values down before typing. Tape measures are easier to read than retyping from memory.
When to Use Each Shape
| Shape | Best for | Skip when |
|---|---|---|
| Rectangle / Square | Standard bedrooms, offices, square rooms. | Room has an alcove or bump-out. |
| Circle | Round patios, pools, gazebos. | Shape is more oval than round — split into sectors instead. |
| Triangle | Attic knee-wall spaces, triangular flower beds. | Any obtuse angle that the base-height model can't capture. |
| Trapezoid | Rooms that taper from wide to narrow (common in older homes). | The two "parallel" sides aren't actually parallel. |
| L-Shape | Living rooms with one alcove or a closet bump. | More than two rectangular sections exist. |
| Irregular | Any room you can draw as the sum of rectangles. | The boundary has curves or diagonals. |
Common Conversions You'll Need
- 1 sq ft = 144 sq in — multiply sq ft by 144 for tile-spacing math.
- 1 sq ft = 0.0929 sq m — multiply sq ft by 0.0929 for metric projects.
- 1 sq yd = 9 sq ft — divide sq ft by 9 for carpet orders priced per yard.
- 1 acre = 43,560 sq ft — divide sq ft by 43,560 for land area.
- 1 square of roofing = 100 sq ft — divide sq ft by 100 for shingle bundles.
Frequently Asked Questions
How do I calculate square footage of a room?
Measure the length and width in feet and multiply them. For a 12 × 10 ft room, that is 12 × 10 = 120 sq ft. For circles, triangles, trapezoids, and L-shapes, switch to the matching shape tab above and the calculator applies the correct formula automatically.
What is the formula for square footage?
Rectangle: length × width. Square: side². Circle: π × r². Triangle: (base × height) / 2. Trapezoid: ((a + b) / 2) × height. L-shape: sum of two rectangles. Irregular: sum of any number of rectangles.
How do I calculate square footage with inches?
Either divide inches by 12 to convert to feet before multiplying, or pick "in" in the unit selector next to each field and the calculator converts for you. You can also mix units across different fields — for example, length in feet and width in inches.
How many square feet is a 10x10 room?
A 10 × 10 ft room is exactly 100 square feet, 9.29 square meters, 11.11 square yards, or 14,400 square inches.
How do I convert square feet to square meters?
Multiply square feet by 0.092903. For example, 100 sq ft × 0.092903 = 9.29 sq m. The reverse is sq m × 10.7639 = sq ft.
Why do I need a waste factor?
Waste factor covers cuts at walls, layout mistakes, broken materials, and a small reserve for future repairs. Ten percent is standard for straight-lay flooring and carpet. Add 15% for diagonal or patterned layouts, and 20% for herringbone or complex tile patterns.
Does the calculator save my measurements?
No. Everything runs in your browser and nothing is uploaded or stored after you close the tab. That also means the calculator works fully offline once the page is loaded.
Can I use this for land or lot size?
Yes for small parcels. The result also shows acres (sq ft ÷ 43,560). For very irregular plots, use the irregular-room tab and split the lot into rectangles using a scaled survey plan.