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Square Footage Calculator
Last updated: June 19, 2026
A square footage calculator is a geometric tool used to determine the area of a two-dimensional space in square feet, typically for real estate, landscaping, and construction planning. It calculates area by multiplying length and width measurements for rectangular spaces, or by summing the areas of individual sub-sections for complex, irregular shapes. It often includes conversions to other units of measurement like square yards, square meters, or acres. Homeowners, contractors, and builders use this tool to estimate material requirements for flooring, drywall, paint, sod, and paving projects.
Enter length and width in any unit. This square foot calculator computes total square feet, square yards, square meters, and acres — perfect for rooms, flooring, walls, and yards.
Quick Answer
Calculate the area of any space in square feet, square yards, or square meters. Enter the length and width in feet or inches to find the total square footage.
Measurement unit
Shape
Material & Cost Estimate (Optional)
Standard is 10% for cuts and edges
Total Square feet
252 sq ft
18 × 14 ft
Calculation Steps:
- Room 1 (rectangle):18 ft × 14 ft = 252 sq ft
- With waste factor:252 × (1 + 0.1) = 277.2 sq ft
Examples
Living room 18 × 14 ft
= 252 sq ft
Kitchen 12 × 10 ft
= 120 sq ft
Backyard 60 × 40 ft
= 2,400 sq ft (≈ 0.055 acres)
Wall 8 ft × 12 ft
= 96 sq ft
How it works
Both length and width are converted to feet, then multiplied. The result in square feet is converted to square yards, square meters, and acres using fixed factors.
Area · L × W = square feet
1 sq yd = 9 sq ft · 1 sq m ≈ 10.764 sq ft · 1 acre = 43,560 sq ft
How to calculate square footage
Calculating the square footage of a standard rectangular room is a simple process. It requires measuring the length and the width of the space and multiplying those two dimensions. For residential real estate, square footage measurements are formally standardized and measured according to the ANSI Z765 standard, which establishes the industry-recognized methodology for calculating finished area in single-family dwellings.
- Measure the length: Use a tape measure to find the distance along one side of the room, from wall to wall. Make sure the tape is straight.
- Measure the width: Measure the perpendicular wall next to the first one, from wall to wall.
- Convert to feet (if necessary): If your measurements include inches, convert them to decimal feet by dividing the number of inches by 12. For example, 10 feet 6 inches becomes 10.5 feet (6 ÷ 12 = 0.5).
- Multiply length by width: Multiply the two measurements together. The formula is:
Length (ft) × Width (ft) = Square Footage (sq ft).
Common Room Sizes in Square Feet
Below is a reference lookup table containing standard residential and commercial room sizes, mapped to their equivalent areas in square feet, square yards, and square meters:
| Room Dimensions | Square Feet (sq ft) | Square Yards (sq yd) | Square Meters (sq m) |
|---|---|---|---|
| 8 × 10 ft | 80 sq ft | 8.89 sq yd | 7.43 sq m |
| 10 × 10 ft | 100 sq ft | 11.11 sq yd | 9.29 sq m |
| 10 × 12 ft | 120 sq ft | 13.33 sq yd | 11.15 sq m |
| 12 × 12 ft | 144 sq ft | 16.00 sq yd | 13.38 sq m |
| 12 × 15 ft | 180 sq ft | 20.00 sq yd | 16.72 sq m |
| 15 × 15 ft | 225 sq ft | 25.00 sq yd | 20.90 sq m |
| 12 × 20 ft | 240 sq ft | 26.67 sq yd | 22.30 sq m |
| 15 × 20 ft | 300 sq ft | 33.33 sq yd | 27.87 sq m |
| 20 × 20 ft | 400 sq ft | 44.44 sq yd | 37.16 sq m |
| 24 × 24 ft | 576 sq ft | 64.00 sq yd | 53.51 sq m |
Calculating Cost Per Square Foot
For many home improvement and construction projects, estimates are calculated using a cost-per-square-foot model. The formula to calculate total cost from square footage is:
Worked Example: If you plan to lay new flooring in a room measuring 240 square feet, and your selected material and labor cost is $4.50 per square foot, the calculation is:
How to measure and calculate different shapes
Depending on the layout of your space, you may need to measure and calculate areas for shapes other than simple rectangles. Here is how to handle each shape supported by this calculator:
- Rectangles: Measure the length and width of the space in feet. Multiply them together.
Formula: Length × Width = Area - Squares: Since all four sides of a square are equal, you only need to measure one side. Multiply the side length by itself.
Formula: Side Length² = Area - Circles: Find the center of the circle and measure the straight line to the outer edge (the radius). Multiply the radius by itself, then multiply by pi (approximately 3.14159).
Formula: π × Radius² = Area - Triangles: Measure the base (flat bottom) and the height (perpendicular distance from base to opposite tip). Multiply the base by the height, then divide by 2 (or multiply by 0.5).
Formula: 0.5 × Base × Height = Area - L-Shaped / Irregular Rooms: Divide the L-shape into two simpler rectangles (Section A and Section B). Calculate the square footage of Section A and Section B separately using the rectangular formula, then add them together.
Formula: (Length A × Width A) + (Length B × Width B) = Total Area
Square footage of irregular or L-shaped rooms
Not all rooms are perfect rectangles. If you are dealing with an L-shaped room, a space with alcoves, or a multi-room project, you can easily calculate the area by breaking the layout down into simpler sections:
- Divide the space: Sketch the room on paper and draw lines to divide it into separate rectangles or squares. For an L-shaped room, draw a single line to split it into two rectangular areas.
- Measure each section: Measure the length and width of each individual section separately.
- Calculate the areas: Multiply the length and width of each section to find its square footage.
- Sum the results: Add the square footages of all the sections together to find the total square footage of the entire space.
Square footage for flooring, paint, and sod
Understanding square footage is the baseline for budgeting and purchasing materials for home improvement projects:
- Flooring (hardwood, laminate, tile): Flooring is sold by the square foot, often packaged in boxes covering a specific square footage. You calculate the room's square footage, add a waste margin (usually 10%), and divide by the square footage per box to determine how many boxes to purchase. Check out our flooring calculator and tile calculator for precise box estimations.
- Paint: One gallon of wall paint generally covers about 350 to 400 square feet with a single coat. To find the wall square footage, measure the wall heights and widths, multiply them, subtract doors and windows, and divide the total area by 350 to find the required gallons of paint. We have a dedicated paint calculator that computes this automatically.
- Landscaping (sod, soil, mulch): Sod is typically sold in rolls or pallets by the square yard or square foot. Measuring the lawn area in square feet helps you order the correct amount of turf grass. If you are ordering bulk soil or mulch, you'll need to combine the square footage with a target depth to compute the volume in cubic yards using our mulch calculator or cubic yard calculator.
Square feet vs square yards vs square meters
Depending on the material or location, you might need to convert your square footage into other units of area:
- Square Yards (sq yd): Mainly used for carpet, turf, and large-scale landscaping. One square yard is a square that measures 3 feet by 3 feet, which equals 9 square feet. To convert square feet to square yards, divide by 9.
- Square Meters (sq m): The standard metric unit of area. One square meter is approximately 10.764 square feet. To convert square feet to square meters, multiply by 0.0929 (or divide by 10.764).
- Acres: Used for large land plots. One acre contains exactly 43,560 square feet. To convert square feet to acres, divide the total area by 43,560.
Worked example: Calculating a living room and hallway
Let's say you want to install new vinyl plank flooring in a rectangular living room that measures 15 feet 4 inches by 12 feet, plus an adjoining hallway that measures 8 feet by 3 feet.
Step 1: Convert measurements to decimal feet
The living room width is 12 feet. The length is 15 feet 4 inches. Convert the 4 inches to feet: 4 ÷ 12 = 0.33 feet. The room length is 15.33 feet.
Step 2: Calculate the area of each section
- Living Room Area: 15.33 ft × 12 ft = 183.96 sq ft
- Hallway Area: 8 ft × 3 ft = 24.00 sq ft
Step 3: Sum the areas for the total
Total Area = 183.96 + 24.00 = 207.96 sq ft
Step 4: Add the 10% cutting waste factor
Waste amount = 207.96 sq ft × 0.10 = 20.80 sq ft.
Total ordering amount = 207.96 + 20.80 = 228.76 sq ft. If flooring is sold in 20 sq ft boxes, you would buy 12 boxes (240 sq ft total).
Common mistakes when measuring area
- Mixing units of measurement: Multiplying inches directly by feet (e.g., 10 feet × 6 inches = 60 square feet) leads to massive errors. Always convert inches to feet by dividing by 12 first.
- Forgetting the waste factor: Ordering the exact square footage of your space will leave you short. You must cut boards or tiles to fit borders, creating scrap. Always add a 10% waste buffer (15% for diagonal layouts).
- Measuring wall-to-wall instead of baseboard-to-baseboard: For flooring projects, ignoring thick wall recesses or door thresholds can leave you slightly short on materials. Always measure to the furthest boundaries where the flooring will actually sit.
- Confusing linear feet with square feet: Linear feet is a measure of straight distance (one-dimensional), while square feet represents surface area (two-dimensional). You cannot buy carpet or sod in simple linear feet without knowing the roll's constant width.
Related measurement and material calculators
Once you know the square footage of your space, use these specialized calculators to estimate exact materials and quantities for your project:
- Area Formula — step-by-step guide to calculating 2D areas.
- Flooring Calculator — box counts for hardwood and laminate.
- Tile Calculator — backing, grout, and tile counts.
- Paint Calculator — wall area paint coverage in gallons.
- Drywall Calculator — sheets, tape, and compound.
- Mulch Calculator — yard soil, compost, and mulch depth.
- Concrete Calculator — slab, footer, and column volume.
- Area Calculator — triangles, circles, and irregular shapes.
- Rectangle Calculator — math for perimeter and diagonals.
Residential measurements comply with the ANSI Z765 standard for measuring finished area. Last reviewed: June 2026.
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Frequently asked questions
Multiply the length by the width of the space, with both numbers in feet. If you measured in inches, divide the number of inches by 12 first to get the decimal feet measurement before multiplying. The calculator handles these conversions for you when you select your measurement units.
Break the irregular layout down into separate, simpler rectangular sections. Measure the length and width of each section to calculate its individual square footage. Then, add the square footages of all the sections together to find the total area.
It is standard practice to add 10% to the total square footage for straight-lay patterns (hardwood, laminate, vinyl, or tile) to cover cuts, border pieces, and mistakes. For diagonal or complex patterns (like herringbone), add 15% for waste.
Measure the exterior walls of each floor of the home, multiply the length by the width, and sum the totals for all stories. Exclude unheated or unfinished spaces like garages, basements, porches, and attics from the livable square footage unless they are fully finished and climate-controlled.
There are exactly 9 square feet in 1 square yard. To convert square feet to square yards, divide your square footage by 9. For example, a 180 sq ft room is equal to 20 square yards (180 ÷ 9 = 20).
There are approximately 10.764 square feet in 1 square meter. To convert square feet to square meters, divide by 10.764 (or multiply by 0.0929).
Linear feet measure a one-dimensional distance (like the length of a board or a fence). Square feet measure a two-dimensional area (like the surface of a floor or wall). You cannot convert linear feet to square feet without knowing the width of the surface.
Multiply the wall's height by its width, and then subtract the area of any doors and windows to find the net paintable surface. A standard door is estimated at 20 square feet, and a standard window is estimated at 15 square feet.
A 12x12 room contains exactly 144 square feet. You can find this total by multiplying the length of 12 feet by the width of 12 feet.
Yes, closets, hallways, and stairs count toward a home's finished square footage, as long as they are heated and finished to the same standard as the rest of the living space. Unfinished basements, garages, and unheated porches are generally excluded from official gross living area calculations.
There are exactly 43,560 square feet in one acre. To convert any large parcel of land between these two units, you can use our free <Link href="/acreage-calculator" className="text-primary hover:text-primary-hover">acreage calculator</Link>.
The ANSI Z765 standard is the voluntary national consensus standard for measuring finished square footage in single-family residential buildings. It mandates that finished spaces must have a ceiling height of at least 7 feet (or 5 feet under sloped ceilings) to be counted as livable area.
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