Square Footage Calculator
Find the square footage of a room, yard, or project. Choose a shape, enter the dimensions in feet, inches, or yards, and get total square feet plus square yards, square meters, cost, and how many boxes of flooring or tile you need — with a conversion table and a downloadable PDF.
| Unit | Total area | With waste |
|---|---|---|
| Enter dimensions to convert | ||
| Waste | Sq ft to buy | Boxes | Cost |
|---|---|---|---|
| Enter dimensions to compare | |||
Square Footage Calculator — Complete Guide for 2026
Square footage is the number behind almost every home project and property decision. Flooring, tile, carpet, sod, pavers, and underlayment are priced by the square foot; rent and home prices are compared per square foot; and contractors quote many jobs the same way. Whether you are buying laminate for a bedroom, laying sod in a backyard, or checking a listing’s size, you need an accurate area measurement first.
Our free Square Footage Calculator handles rectangles, circles, and triangles, with a separate feet, inches, or yards unit for each dimension and a number-of-areas multiplier for identical rooms. It returns total square feet, the area to buy with waste, square yards, square meters, and acres, plus how many boxes of flooring or tile you need and an estimated cost. A unit conversion table, a waste-allowance table, a chart, and a downloadable PDF round it out.
How to Use the Square Footage Calculator in 4 Steps
A complete measurement takes under a minute. Pick a shape, enter your dimensions as measured, add waste and box coverage, and download a PDF to take to the flooring store or share with an installer.
Choose a Shape & Enter Dimensions
Select Rectangle (length × width), Circle (diameter), or Triangle (base × height). Enter each dimension with its own unit — feet, inches, or yards. If you have several identical spaces, such as three matching bedrooms, set the Number of areas. Results update live on every keystroke.
Add Waste & Box Coverage
Enter a waste / overage percentage for cuts, pattern matching, and mistakes — 10% is the default. Enter the coverage per box in square feet from the product label and the calculator tells you how many boxes to buy, rounded up to whole boxes. Leave coverage at 0 to skip it.
Enter a Price per Square Foot
Add the material’s price per square foot — flooring, tile, sod, pavers, or anything priced by area — to see an estimated cost. The estimate is based on the area plus waste, because that is the amount you actually buy. Leave the price at 0 to skip cost.
Review & Download the Report
The hero result shows total square footage. Cards add the area with waste, square yards, and boxes; the summary adds square meters, acres, and cost. The conversion table shows your area in five units, and the waste table and chart compare 0% to 20% waste side by side. Click Download report for a branded PDF.
What a Square Foot Is — and the Three Shape Formulas
A square foot is the area of a square 1 foot on each side — 12 in × 12 in = 144 square inches. Because area multiplies two lengths, unit conversions are squared too: 1 square yard is 3 ft × 3 ft = 9 square feet, not 3, and 1 square meter is about 10.764 square feet (1 sq ft = 0.09290304 m² exactly, from 1 ft = 0.3048 m). One acre is 43,560 square feet.
Every area formula needs both dimensions in the same unit. Multiplying 15 feet by 144 inches gives 2,160 — a number that is neither square feet nor square inches. Convert first (144 in ÷ 12 = 12 ft), then multiply: 15 × 12 = 180 sq ft. The calculator’s per-field unit selectors convert every dimension to feet before applying the formula.
The three shapes the calculator handles
- Rectangle or square: length × width. Covers most rooms, patios, decks, and lawns.
- Circle: π ÷ 4 × diameter², or about 0.7854 × d². Measuring the diameter across the widest point is easier than finding the exact center for a radius. A 12 ft circle is 113.1 sq ft.
- Triangle: ½ × base × height, with the height measured at a right angle to the base. Useful for corner beds, angled walls, and gable ends. A 12 ft base with an 8 ft height is 48 sq ft.
Anything more complex — an L-shaped living room, a bay window, a kidney-shaped patio — is handled the same way professionals do it: split it into rectangles, circles, and triangles, calculate each, and add them together.
What the Square Footage Calculator Calculates
Every output comes from the same shape, dimensions, and area count, so square footage, the amount to buy, box count, and cost always agree with each other and with the tables and chart.
Total Square Footage (Hero Result)
Area per unit × number of areas, shown to one decimal. The breakdown also shows the area per unit so you can check each room. At the default inputs — a 15 ft × 12 ft rectangle — the result is 180 sq ft.
Area with Waste
Total square feet × (1 + waste %) — the amount of material to buy, covering cuts, offcuts, pattern matching, and mistakes. With the default 10%, 180 sq ft becomes 198 sq ft. The box count and cost are both based on this number.
Boxes Needed
Area with waste ÷ coverage per box, always rounded up to a whole box — stores don’t sell partial boxes. At 20 sq ft per box, 198 sq ft is 9.9 boxes, so you buy 10. If coverage is left at 0, this card shows square meters instead.
Square Yards, Meters, Inches & Acres
Square yards (sq ft ÷ 9) are used for carpet and some sod; square meters (sq ft × 0.09290304) for imported products and international specs; square inches (sq ft × 144) for small tile work; acres (sq ft ÷ 43,560) for lots and land. Defaults: 20.00 yd², 16.72 m², 25,920 in², 0.0041 acres.
Conversion & Waste Tables + Chart
The conversion table shows your area in square feet, square yards, square meters, square inches, and acres — both as measured and with waste. The waste table shows square feet to buy, boxes, and cost at 0%, 5%, 10%, 15%, and 20%, and the bar chart plots square feet to buy at each allowance.
Estimated Cost & PDF Report
Cost = area with waste × price per square foot — the defaults give $990 at $5/sq ft. The PDF includes a branded header, the total square footage, an inputs-and-results table, the unit conversion table, the waste-allowance table, and a tip for splitting odd shapes.
Square Footage Chart — Common Room & Project Sizes
Areas below are before any waste allowance. Highlighted rows mark the most common room and project sizes.
| Shape & Dimensions | Square Feet | Square Yards | Square Meters | Common Reference |
|---|---|---|---|---|
| 36 in × 60 in | 15.00 sq ft | 1.67 yd² | 1.39 m² | Mixed units — shower or bath floor area |
| Triangle, 12 ft base × 8 ft high | 48.00 sq ft | 5.33 yd² | 4.46 m² | Corner bed or gable end |
| Circle, 10 ft diameter | 78.54 sq ft | 8.73 yd² | 7.30 m² | Round patio or fire-pit area |
| 10 ft × 10 ft | 100.00 sq ft | 11.11 yd² | 9.29 m² | Small bedroom, office, or patio |
| Circle, 12 ft diameter | 113.10 sq ft | 12.57 yd² | 10.51 m² | Round deck or large rug zone |
| 10 ft × 12 ft | 120.00 sq ft | 13.33 yd² | 11.15 m² | Kitchen or small bedroom |
| 12 ft × 12 ft | 144.00 sq ft | 16.00 yd² | 13.38 m² | Standard bedroom |
| 15 ft × 12 ft | 180.00 sq ft | 20.00 yd² | 16.72 m² | Calculator default — larger bedroom |
| 12 ft × 18 ft | 216.00 sq ft | 24.00 yd² | 20.07 m² | Primary bedroom or family room |
| Circle, 20 ft diameter | 314.16 sq ft | 34.91 yd² | 29.19 m² | Round lawn or pool surround |
| 20 ft × 20 ft | 400.00 sq ft | 44.44 yd² | 37.16 m² | Large living area or deck |
| 24 ft × 24 ft | 576.00 sq ft | 64.00 yd² | 53.51 m² | Two-car garage |
| 30 ft × 40 ft | 1,200.00 sq ft | 133.33 yd² | 111.48 m² | Small home footprint or backyard lawn |
| 1 acre | 43,560.00 sq ft | 4,840.00 yd² | 4,046.86 m² | Land and lot measurement |
Areas exclude waste. Add your overage percentage (commonly around 10% for straight-lay flooring and more for diagonal patterns) before buying material.
Square Footage — Unit Conversions and Shape Formulas
Area units convert by the square of the length factor, which is where most mistakes happen. The table on the left lists the area conversions you’ll use most; the table on the right collects the formulas for common shapes, including ones you can build from the calculator’s rectangle, circle, and triangle options.
| Unit | Equals | In sq ft |
|---|---|---|
| 1 sq in | 1 in × 1 in | 0.00694 sq ft |
| 1 sq ft | 12 in × 12 in | 144 sq in |
| 1 sq yd | 3 ft × 3 ft | 9 sq ft |
| 1 sq m | metric | 10.764 sq ft |
| 1 sq ft | metric | 0.0929 m² |
| 1 acre | 4,840 sq yd | 43,560 sq ft |
| 1 hectare | 10,000 m² | 107,639 sq ft |
| 1 sq mile | 640 acres | 27,878,400 sq ft |
| Shape | Formula | Example |
|---|---|---|
| Rectangle | L × W | 15 × 12 = 180 sq ft |
| Square | side² | 12² = 144 sq ft |
| Circle | π ÷ 4 × d² | 12 ft ⌀ = 113.1 sq ft |
| Half circle | π ÷ 8 × d² | 12 ft ⌀ = 56.5 sq ft |
| Triangle | ½ × b × h | 12 × 8 ÷ 2 = 48 sq ft |
| L-shape | two rectangles | 240 + 80 = 320 sq ft |
| Trapezoid | ½ × (a + b) × h | (10 + 14) ÷ 2 × 8 = 96 sq ft |
Square Footage — Key Numbers
The Square Footage Calculator Is Built For You If…
Whether you’re buying flooring for a bedroom, quoting a tile job, or sizing up a rental or listing, this calculator turns tape-measure dimensions into square footage, material quantities, and cost in seconds.
Homeowners & DIY Renovators
Flooring, tile, carpet, sod & paversYou’re standing in the flooring aisle and the box says it covers 20 sq ft. A homeowner re-flooring a 15 × 12 ft bedroom needs 180 sq ft, 198 with 10% waste — so 10 boxes. Someone laying sod on a round lawn feature or tiling a triangular corner can switch shapes instead of guessing, and the cost estimate shows the budget before checkout.
- Measure each wall-to-wall dimension at two or three points and use the largest
- Enter coverage per box from the label to get a rounded-up box count
- Split L-shaped rooms into rectangles and add the totals
- Bring the PDF to the store or share it with your installer
Flooring, Tile & Paint Contractors
Quotes, material orders & job sheetsQuotes are built on square footage, and ordering short means a second trip or a dye-lot mismatch. An installer quoting three identical bedrooms can enter one and set the area count to 3. The waste table makes it easy to show a client why a herringbone layout needs more material than a straight lay — and what it costs.
- Use the area count for repeated rooms in apartments or tract homes
- Show clients the 10% vs 15% vs 20% waste comparison before ordering
- Order all boxes from the same lot to avoid shade variation
- Attach the PDF to quotes, work orders, and supplier orders
Buyers, Renters & Real Estate Pros
Listings, price per sq ft & space planningPrice per square foot is one of the most common ways to compare homes and rentals. Buyers checking whether a room matches its listing, renters comparing apartments, and agents or landlords measuring spaces all need quick, reliable area numbers. Square meters and acres are there for international buyers and lot sizes.
- Measure each room and add the totals to compare against a listing
- Divide price or rent by total square feet to compare properties
- Official listing and appraisal figures follow specific measuring standards
- Use acres for lot size and square meters for international buyers
7 Tips for Accurate Square Footage Measurements
The formulas are simple, but out-of-square walls, mixed units, and forgotten closets are behind most short orders. These tips help you measure once and buy the right amount.
Measure Wall to Wall at More Than One Point
Real rooms are rarely perfectly square. Measure each dimension at two or three points and use the largest figure for material estimates. Measure from finished wall to finished wall, and round up to the next half foot or inch rather than down.
Keep Both Dimensions in the Same Unit
Feet × inches is not square feet. Convert first — inches ÷ 12, yards × 3 — or multiply inches by inches and divide by 144. The calculator’s unit selectors do this automatically, so enter each measurement exactly as you took it.
Split Irregular Spaces Into Simple Shapes
Break L-shaped rooms, bay windows, and curved beds into rectangles, circles, and triangles. Calculate each piece and add the results. For a half-circle, calculate the full circle and halve it. Subtract large fixed items like a kitchen island only if the material won’t go under them.
Don’t Forget Closets, Nooks, and Transitions
Closets, pantries, hallways, and doorway transitions are easy to miss and often use the same flooring as the main room. Measure them separately and include them, or add a larger waste allowance to cover them.
Match Waste to the Layout Pattern
About 10% is a common allowance for flooring and tile laid in a straight pattern. Diagonal, herringbone, large-format tile, and patterned material often need 15–20%. Rooms with many corners or cutouts also need more. Check the manufacturer’s or installer’s recommendation, and use the waste table to compare.
Buy Whole Boxes From the Same Lot
Materials are sold in whole boxes, so always round up — the calculator does this for you. Buy every box you need from the same production lot to avoid shade or size variation, and keep a spare box or two for future repairs.
Know That Listing Square Footage Is Measured Differently
Square footage for flooring is the floor area you cover. Official home size for listings and appraisals is typically measured from the exterior and follows specific standards on what counts, such as whether garages, basements, or low-ceiling areas are included. Use this calculator for project areas and room checks, and rely on the appraisal or official records for a home’s official size.
Square Footage Calculator — Frequently Asked Questions
Everything you need to know about calculating square footage for rooms and projects, handling circles, triangles, and irregular spaces, converting units, and figuring how much flooring or tile to buy.
For a rectangle or square, multiply the length by the width, with both measured in feet. The formula is: square feet = length (ft) × width (ft). For example, a 15 ft × 12 ft room is 15 × 12 = 180 square feet.
If a measurement is in inches, divide it by 12 first; if it is in yards, multiply it by 3.
Split the space into simple rectangles, circles, or triangles, calculate each one, and add them together. For example, an L-shaped room made of a 20 ft × 12 ft section and a 10 ft × 8 ft section is 240 + 80 = 320 square feet.
Run each shape through the calculator separately and add the totals.
Multiply the diameter squared by pi divided by 4 (about 0.7854). The formula is: square feet = π ÷ 4 × diameter². For example, a 12 ft diameter circle is 0.7854 × 144 = 113.1 square feet.
This is the same as π × radius², using half the diameter.
Multiply the base by the height and divide by 2. The formula is: square feet = ½ × base × height, where the height is measured at a right angle to the base.
For example, a triangle with a 12 ft base and 8 ft height is 12 × 8 ÷ 2 = 48 square feet.
Either convert each measurement to feet by dividing by 12 before multiplying, or multiply the inches together and divide the result by 144, since 1 square foot = 144 square inches. For example, 36 in × 60 in = 2,160 square inches ÷ 144 = 15 square feet.
The calculator lets you choose inches, feet, or yards for each dimension and converts automatically.
Add your waste allowance to the square footage, then divide by the square feet each box covers and round up. For example, a 180 sq ft room plus 10 percent waste is 198 sq ft; at 20 sq ft per box that is 9.9, so buy 10 boxes.
Enter the coverage from the product label and the calculator rounds up to whole boxes for you.
About 10 percent is a common allowance for flooring and tile laid in a straight pattern. Plan for more, often 15 to 20 percent, for diagonal or herringbone layouts, large-format tile, patterned material that must be matched, or rooms with many corners and cutouts.
Check the manufacturer’s or installer’s recommendation for your specific product.
Divide square feet by 9 to get square yards, because 1 square yard is 3 ft × 3 ft = 9 sq ft. Multiply square feet by 0.09290304 to get square meters, or divide by about 10.764.
For example, 180 sq ft = 20 square yards = 16.72 square meters. One acre is 43,560 square feet.
The area math is exact: each dimension is converted to feet (1 in = 1/12 ft, 1 yd = 3 ft) and then rectangle = length × width, circle = π ÷ 4 × diameter², and triangle = ½ × base × height, calculated with double-precision arithmetic. Square meters use the exact factor 1 sq ft = 0.09290304 m².
Your result is only as accurate as your measurements, and real rooms are rarely perfectly square, so measure at more than one point and buy extra for waste.
Accuracy note: The HomeExpertly Square Footage Calculator converts each dimension to feet using the exact relationships 1 in = 1/12 ft and 1 yd = 3 ft, then applies length × width for rectangles, π ÷ 4 × diameter² for circles, and ½ × base × height for triangles, multiplied by the number of areas. Unit conversions use 1 sq yd = 9 sq ft, 1 sq ft = 144 sq in, 1 sq ft = 0.09290304 m² (exact), and 1 acre = 43,560 sq ft. Box counts are rounded up to whole units from the coverage you enter, and cost estimates depend entirely on the price you enter and exclude underlayment, trim, adhesives, taxes, delivery, and labor. Results are for informational and planning purposes only. Square footage for a project is not the same as a home’s official living area, which is measured under specific standards for listings, appraisals, and tax records. Before buying materials, verify measurements and quantities with your retailer or installer, and rely on a licensed appraiser or official records for a property’s official size. HomeExpertly is not responsible for any consequences arising from the use of these estimates.