HOME CALCULATOR
Square Footage Calculator for Rooms and Floors
Calculate square feet for rooms, floors, walls, and other surfaces. Add a waste allowance, convert between common area units, and estimate how much material you may need.
Measure Area and Plan Materials
Measure an area, add waste, and estimate material needs.
Area shape
Dimensions
Material planning
Coverage and price are optional. Enter the manufacturer coverage or your quoted price when available.Results update when you select Calculate. Measurements are converted to square feet for the main result.
Area diagram
Visual reference for the selected shape and its area formula.
Area breakdown
See how the waste allowance changes the amount to order.
Calculation summary
Every step used to reach the final square footage.
| Measurement | Value | Square feet |
|---|---|---|
| Area formula | Rectangle | L × W |
| One area | 120 ft² | 120 ft² |
| Number of areas | 1 | 120 ft² |
| Waste allowance | 10% | 12 ft² |
| Total to plan for | Including waste | 132 ft² |
Material estimate
Optional estimate based on the coverage you entered.
Round up because partial boxes, rolls, or packages generally cannot cover a complete project.
Cost estimate
Optional planning estimate using your price per square foot.
This is a material-only estimate and does not include labor, delivery, tax, underlayment, adhesive, or other project costs.
What Is Square Footage?
Square footage is a measurement of area. It tells you how much two-dimensional space a surface covers, usually expressed in square feet (ft²). It is commonly used when estimating flooring, tile, carpet, paintable wall area, roofing materials, landscaping surfaces, and the size of rooms or other spaces.
For a simple rectangular room, multiply the length by the width. A room that is 12 feet long and 10 feet wide has 120 square feet. If you are measuring several spaces, calculate each space separately and add the results together.
How to Calculate Square Feet
The formula depends on the shape of the surface. Most rooms and floors are rectangles, but squares, triangles, and circles can also be measured using simple area formulas.
| Shape | Formula | Example |
|---|---|---|
| Rectangle | Length × width | 12 ft × 10 ft = 120 ft² |
| Square | Side × side | 10 ft × 10 ft = 100 ft² |
| Triangle | Base × height ÷ 2 | 12 ft × 8 ft ÷ 2 = 48 ft² |
| Circle | π × radius² | 10 ft diameter ≈ 78.54 ft² |
Rectangular rooms
Measure the length and width of the room in the same unit, then multiply them. A 15 ft × 12 ft room has an area of 180 ft². If the room contains an alcove or another irregular section, divide the surface into simple shapes and add the areas.
Squares
A square has four equal sides, so only one side measurement is needed. If every side is 14 feet, the area is 14 × 14 = 196 ft².
Triangles
Multiply the base by the perpendicular height and divide by two. The height is measured at a right angle to the base; it is not necessarily the length of one of the sloping sides.
Circles
A circular surface uses πr². If you measure the diameter, divide it by two to get the radius. This calculator accepts diameter directly and performs that conversion for you.
Square Feet, Square Meters, and Square Yards
Suppliers and construction projects do not always use the same area unit. Converting between units makes it easier to compare product coverage and measurements.
| Area unit | Equivalent | Common use |
|---|---|---|
| 1 ft² | 0.092903 m² | US flooring and room measurements |
| 1 m² | 10.7639 ft² | Metric building and material specifications |
| 1 yd² | 9 ft² | Carpet, fabric, and some surface materials |
How Much Waste Should You Add?
Waste depends on the material and the shape of the project. A simple rectangular floor with straight cuts may require less extra material than a room with many corners, diagonal cuts, patterns, or complicated layouts. That is why this calculator lets you enter your own waste percentage.
For flooring and tile, extra material can also be useful for future repairs. The appropriate allowance varies, so compare your estimate with the installation guidance from the manufacturer or supplier.
How to Measure an Irregular Room
- Sketch the room and record the major wall measurements.
- Divide the shape into rectangles, triangles, or other simple sections.
- Calculate the area of each section separately.
- Add all section areas together.
- Add a material-specific waste allowance.
An L-shaped floor, for example, can usually be divided into two rectangles. If you need a broader geometry tool, the Area Calculator can also help with general area calculations.
Square Footage for Flooring and Tile
When buying flooring or tile, start with the measured floor area. Add the appropriate waste allowance, then divide the planning area by the coverage printed on the product package. Always round up to a complete box or package.
If a project changes from a two-dimensional surface measurement to a three-dimensional material quantity, the Volume Calculator can help. For slabs and other concrete projects, the Concrete Calculator estimates concrete volume.
Square Footage Example
Suppose you are installing flooring in a 20 ft × 15 ft room and want to allow 10% for waste. The actual floor area is 300 ft². A 10% allowance adds 30 ft², giving a planning total of 330 ft². If one box covers 22 ft², divide 330 by 22 and round up to the next whole box.
Keeping actual area separate from planning area makes it easier to compare supplier quotes and package coverage. The actual area describes the surface itself; the planning area includes the additional material allowance.
Square Footage for Walls
Wall area is also measured in square feet, but the dimensions are width and height rather than floor length and width. For one rectangular wall, multiply width by height. If you are painting or covering multiple walls, calculate each wall separately and consider subtracting large doors and windows when precision matters.
Square Footage for Paint
Paint projects require an additional step because paint is normally sold according to coverage per gallon or liter rather than square footage alone. Measure the wall area, account for openings and the number of coats, then compare the result with the manufacturer's stated coverage. Surface texture and application method can also affect actual coverage.
Square Footage for Carpet and Flooring
Carpet, laminate, vinyl, hardwood, and other flooring products are often sold by square foot, square yard, box, roll, or package. Use the calculator to establish the area first, then use the product's actual coverage to determine the purchase quantity.
Patterned flooring can require more waste because pieces may need to be aligned. Rooms with many corners can also require more cutting than a simple rectangle.
Common Square Footage Mistakes
- Mixing units: Convert dimensions to the same unit before multiplying.
- Using diameter as radius: A circle's radius is half its diameter.
- Forgetting multiple sections: Add every room or section that receives the material.
- Ignoring waste: Cutting, breakage, seams, and pattern matching can increase the amount you need to buy.
- Rounding too early: Keep decimals during the calculation and round the final package quantity.
- Confusing area and perimeter: Area measures surface coverage; perimeter measures the distance around an edge.
Square Footage for Home Projects
Square footage is one of the most useful measurements for planning a home project because many products are sold by coverage area. It can be used for flooring, tile, carpet, paint, roofing products, artificial grass, landscaping surfaces, and many other materials.
The final purchase quantity should still be checked against product dimensions, package coverage, installation method, cutting pattern, and manufacturer recommendations. A mathematical area calculation cannot account for every installation condition.
Frequently Asked Questions
How do I calculate the square footage of a room?
Measure the room length and width in the same unit and multiply them. For example, 12 ft × 10 ft = 120 ft².
How many square feet are in a square meter?
One square meter is approximately 10.7639 square feet. The calculator converts between the units automatically.
Should I add waste when calculating flooring?
Usually, some allowance should be made for cutting, breakage, pattern matching, and installation conditions. The appropriate percentage depends on the project and material.
How do I calculate square footage for an L-shaped room?
Divide the L-shape into two or more simple rectangles, calculate each rectangle, and add the areas together.
Is square footage the same as square feet?
In everyday usage, they describe the same area measurement. Square feet is the unit, while square footage describes the amount of area measured in square feet.
How do I calculate square footage from inches?
Convert each dimension to feet before multiplying, or calculate square inches and divide by 144. This calculator can accept inches directly.
How do I estimate the number of flooring boxes?
Calculate the total area including waste, divide it by the coverage per box, and round up to the next whole box.
Can I use this calculator for wall area?
Yes. Measure the wall width and height and treat the surface as a rectangle. For multiple walls with matching dimensions, the quantity field can be useful.