Square Footage Calculator
Measure two walls and you're most of the way to an accurate square footage number. The part that trips people up is everything after that: odd angles, bump-outs, and the conversion to square yards that flooring stores actually price by.
Square Footage Calculator
Enter your measurements below for an instant quantity estimate.
For L-shaped rooms, add a second rectangle. Leave at 0 for a plain rectangle.
For rooms with more than two rectangular sections, run the calculator once per section and add the totals by hand.
Measure at the Floor, Not the Baseboard
Run the tape along the floor, wall to wall, not along the trim. Baseboards and door casing can add an inch or two of visual clutter that throws off a precise number, and for anything you're buying by the square foot, like flooring or tile, that difference adds up over a whole room.
- For a simple rectangular room, one length and one width measurement is all you need.
- For an L-shaped room, split it into two rectangles and enter both in the calculator below.
- For anything more irregular, break it into as many rectangles as it takes and add the totals by hand.
Square Feet, Square Yards, and Square Meters Aren't Interchangeable
Flooring contractors quote hardwood and tile by the square foot. Carpet installers almost always quote by the square yard, which is nine square feet, not one. Mix those up on a big room and you'll either underbuy carpet or overpay for a hardwood quote that was never in square yards to begin with. If you're working from a Canadian supplier's quote, square meters show up too: one square meter is roughly 10.76 square feet.
Common Room Sizes as a Sanity Check
A typical single-car garage runs about 200 to 250 square feet, a two-car garage closer to 400. A standard bedroom lands somewhere between 130 and 200 square feet, and a full basement in a typical suburban home often comes out between 800 and 1,500 square feet depending on the house. These aren't rules, just reference points: if your calculated number is wildly outside a reasonable range for the kind of room you're measuring, it's worth re-measuring before you order flooring or submit a number to a supplier.
Why Contractors Ask for Square Footage Before Quoting
Square footage is the first number almost every contractor asks for because most trade pricing, flooring, painting, drywall, roofing, is quoted per square foot. Handing a contractor an accurate number upfront, rather than a rough guess, gets you a tighter, more reliable quote and avoids the awkward moment where a final bill runs higher because the actual room turned out bigger than what you originally described over the phone.
Frequently Asked Questions
How do you calculate square footage?
Multiply length by width, both in feet. A 10-foot by 12-foot room is 120 square feet. That's the whole formula for a rectangle; anything more irregular just means splitting the space into rectangles first and adding the results.
How do I measure a room that isn't a perfect rectangle?
Split it into two or more rectangles, measure each one separately, and add the areas together. This calculator has a second length and width field built in specifically for L-shaped rooms; for anything more complex, run the calculator once per rectangle and add the results yourself.
How many square feet is a 12x12 room?
144 square feet. That's a common bedroom size, and it's also a useful benchmark: if a room you're measuring comes out well under 100 square feet or well over 300, double-check your tape measurements before ordering material.
Does square footage include closets?
It depends on why you're measuring. For paint, no, since you're not painting a fully separate room. For flooring, usually yes, since the flooring runs through the closet too. When in doubt, measure the closet separately and decide based on what you're actually buying.
What's a fast way to estimate square footage without a tape measure?
Count floor tiles or hardwood plank widths if the room already has them, since manufacturers list standard sizes. It's not perfectly precise, but it gets you in the right range faster than pacing off a room in footsteps.
Should I round my measurements up or down before calculating?
Round up. A slightly generous square footage number means you buy a touch more material than strictly needed, which is far less costly than running short mid-project and needing a second trip for a small top-up order.
Does an L-shaped calculation work for a U-shaped room too?
Not directly with just two rectangles. For a U-shaped or more complex room, split it into three or more rectangles, run this calculator once per section, and add the totals together by hand.
Why does my contractor's square footage number differ from mine?
Contractors sometimes measure exterior wall dimensions, from outside the framing, rather than interior floor space, which yields a larger number than what you'd measure standing inside the room. Ask which method they used before comparing it to your own calculation.
Is garage square footage counted the same as living space?
Not usually in real estate listings, where garages, unfinished basements, and porches are typically listed separately from 'living area' square footage, even though they're still real, measurable space for a renovation project.
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