Square Footage Calculator

Square footage is the area of a flat surface measured in square feet: the number of 1 ft × 1 ft squares it would take to cover it. Pick the shape that matches your space, enter its measurements in any unit, and the calculator converts them and returns the area in square feet, square meters, square yards and acres. Irregular rooms can be split into rectangles and triangles, calculated separately and added together.

Reference:

Common area conversions, useful when product prices and plans use different units:

Calculating Cost Per Square Foot

Many materials and services are priced per unit of area. Enter the price and its unit in any form above and the calculator multiplies it by the area. To go the other way, divide a total price by the square footage to get the cost per square foot, which makes quotes and listings of different sizes comparable.

Painting a house:

Paint is estimated from wall area, not floor area. For each wall, multiply its width by the ceiling height, add the walls together, and subtract large openings: a standard door is about 20 square feet and an average window about 15. A 12 × 14 ft room with 8 ft ceilings has 2 × (12 + 14) × 8 = 416 square feet of wall; minus one door and two windows, that leaves about 366 square feet.

A gallon of interior paint typically covers 350 to 400 square feet per coat on smooth, primed walls, according to most manufacturers' labels. Rough or porous surfaces such as new drywall, stucco or bare wood absorb more, and dramatic color changes usually need two coats or a tinted primer. For the example room, two coats need roughly 730 square feet of coverage, or two gallons. Ceilings are estimated separately from the floor area.

Flooring installation:

Flooring is sold by the square foot (carpet sometimes by the square yard), so the area of the room is the starting point. Measure at the widest points, including closets and the space under built-in appliances only if the floor will run beneath them, and split L-shaped rooms into rectangles.

Then add an allowance for waste. Cutting boards or tiles to fit walls, doorways and irregular edges always leaves offcuts. About 5 to 10 percent extra is typical for straight-lay planks and tile, 10 to 15 percent for diagonal patterns or rooms with many corners, and more for herringbone. Extra material also lets you replace damaged pieces later with an exact match from the same production lot.

Installed cost has two parts: the material price per square foot and the labor rate, which depends on the product and region. Floating floors and luxury vinyl plank are among the quickest to install, while tile needs a flat, stiff subfloor, setting material and grout, and often costs more to install than the tile itself. Remember to budget for underlayment, transitions, baseboard or shoe molding, and removal of the old flooring.

If you are carpeting, note that broadloom carpet comes in fixed widths, commonly 12 feet, so seam placement can raise the amount you buy above the room's exact area.

Building a home:

Builders, appraisers and listing services quote home size as finished square footage and often compare homes by price per square foot. In the US, the ANSI Z765 standard, widely used by appraisers, measures the exterior dimensions of each finished level and sets rules for what counts. Finished area must be heated, walled and floored like the rest of the house, and areas below grade are reported separately from above-grade living area.

Construction cost per square foot varies widely with location, finishes, the shape of the house and site work, so use local quotes rather than national averages. A compact, rectangular plan costs less per square foot to build than one with many corners, while kitchens and bathrooms are the most expensive rooms per square foot because of plumbing, cabinets and fixtures. Garages and unfinished basements cost less to build but do not count as living space.

Frequently asked questions