Square Footage Calculator

You're standing in your living room with a tape measure in one hand and your phone in the other, trying to figure out how much flooring you actually need. Sound familiar? That's exactly what this square footage calculator is built for.

Plug in your room's width and length, and you'll get an instant area calculation. But here's where it gets really useful: enter the price per square foot of your chosen material, and the calculator tells you what you're looking at in total material costs. No spreadsheet required.

It handles unit conversions between feet, inches, meters, and more, so you don't have to do that math yourself. And if you're working on multiple rooms with the same dimensions, the quantity field saves you from running the same calculation over and over.

Square footage measures the area of a flat surface in square feet. One square foot is a 12-inch by 12-inch square - roughly the size of a standard floor tile.

That number follows you everywhere in home projects. It's how flooring is priced at the store. It's how painters estimate a job. It's how contractors write up quotes. Get your square footage wrong, and everything downstream - your material order, your budget, your timeline - goes sideways.

The most expensive mistake isn't buying too much material. It's buying too little. Running short mid-project often means a second trip to the store, and there's no guarantee you'll find the same dye lot or product batch. With tile especially, even slight color variations between batches are noticeable once they're installed next to each other.

The math is simple:

Area = Width x Length

A room that's 12 feet wide and 15 feet long? That's 180 square feet.

If your measurements aren't in feet, convert them first:

Quick example with mixed measurements: Your room is 12 feet and 6 inches wide. Convert those 6 inches: 6 / 12 = 0.5 feet. So your width is 12.5 feet. If the length is 15 feet, the area is 187.5 square feet.

For multiple identical spaces, just multiply. Three bedrooms at 144 square feet each? That's 432 square feet total - enter 144 once and set the quantity to 3.

1. Enter the width and select your unit from the dropdown. The calculator supports feet, inches, meters, centimeters, and yards.
2. Enter the length and pick its unit. The two don't need to match - if you measured width in feet and length in meters, the calculator converts automatically.
3. Set the quantity. One room? Leave it at 1. Three identical guest bedrooms? Set it to 3 and save yourself the repetition.
4. Read your total area. Switch the Area Unit dropdown to see the result in square feet, square meters, square inches, or square yards - whichever your supplier uses.
5. Enter a unit price to get a cost estimate. Type in the material's price per square foot (or per whatever unit you selected), and the total cost appears instantly.

Dry formulas only get you so far. Here's how the numbers actually play out on common projects:

Replacing a living room floor Say you're putting engineered hardwood in a 20 ft x 15 ft living room. That's 300 square feet. Engineered hardwood runs about $5.50 per square foot at mid-range quality, so materials come to $1,650. Add 10% for waste (cuts at doorways, closets, and along walls), and you're looking at about $1,815 before installation.

Tiling a bathroom Bathrooms are small but expensive per square foot because of all the cuts around fixtures. An 8 ft x 10 ft bathroom is 80 square feet. Porcelain tile at $4.00 per square foot is $320 in materials - but bump your waste factor to 15% because of cuts around the toilet, vanity, and tub. That puts you closer to $368. And buy a few extra tiles to keep in the garage for future repairs. Cracking a tile in five years and not being able to match it is a headache you can avoid for a few dollars now.

Painting a bedroom A 14 ft x 12 ft bedroom has 168 square feet of floor space, but you're painting the walls, not the floor. Calculate perimeter first: (14 + 12) x 2 = 52 linear feet. Multiply by the 8-foot ceiling height for 416 square feet of wall area. A gallon of paint covers roughly 350 square feet, so you'll need about 2 gallons for a single coat. Plan on two coats with fresh color, which means 4 gallons total.

Building a deck A 16 ft x 12 ft deck is 192 square feet. Composite decking at $8.00 per square foot puts your materials at $1,536. But decking waste runs higher than flooring because of joist spacing and end cuts - budget 12-15% extra, bringing you to roughly $1,750.

Carpeting multiple bedrooms Three bedrooms, each 12 ft x 12 ft, at 144 square feet per room. Set quantity to 3: 432 square feet total. Mid-range carpet at $3.50 per square foot totals $1,512. With 10% for seaming and doorway transitions, plan for about $1,663. One tip: carpet remnants from the same roll are usually cheaper per square foot if your rooms are small enough. Ask your retailer.

The accuracy of your cost estimate depends entirely on the price you enter. Here's where common materials typically land so you can ballpark your project before heading to the store:

Flooring

Other Projects

Watch out for unit mismatches. Some retailers price tile per piece, not per square foot. Lumber is often sold per board foot or linear foot. Carpet stores sometimes quote per square yard. Always convert to price per square foot before plugging numbers into the calculator, or you'll get a cost estimate that's way off.

Your calculation is only as good as the measurements you feed it. These habits keep your numbers accurate:

• Measure at least twice. A single wrong number can mean a short material order and a mid-project scramble. If your two measurements don't match exactly, use the larger one.
• Measure at the longest and widest points. Rooms are rarely perfectly square. Walls bow, corners aren't true 90 degrees. Measuring at the maximums ensures you buy enough material. A small surplus is always cheaper than a shortage.
• Split irregular rooms into rectangles. An L-shaped kitchen is just two rectangles. Measure each section, calculate both areas, and add them together. Same approach works for T-shapes, U-shapes, or any odd layout.
• Include or exclude obstacles intentionally. Closets get carpet but not tile. Kitchen islands subtract from your tile area. Built-in bookshelves subtract from your wall painting area. Think through what actually gets covered before you calculate.
• Factor in waste by project type. Standard straight-lay flooring: 5-10% extra. Diagonal installations: 10-15%. Herringbone or chevron patterns: 15-20%. The more cuts your layout requires, the more waste you'll produce.
• Keep a few extras. For tile and hardwood, buy one or two boxes beyond your waste factor. Store them in the garage. When a tile cracks or a plank gets scratched in three years, you'll have a perfect match on hand instead of hunting for a discontinued product.

Helpful for quick estimates when you haven't measured yet:

These are averages for U.S. residential construction. Your rooms may be larger or smaller, so always measure before ordering materials.