How to calculate square feet of a room
- Clear the edges of the room and measure its longest length from wall to wall at floor level.
- Measure the width the same way, from wall to wall at floor level.
- Turn any inches into feet by dividing by 12, so 6 inches is 0.5 feet.
- Multiply the length in feet by the width in feet to get square feet.
- For an odd shape, split the floor into rectangles and enter each one in its own row to add them up.
How to calculate the square footage of a house
Work out each room, hallway and closet, then add them together. Add a row above for each one and the total updates as you type. For a house with more than one story, count the floor area of every story.
A listed home's square footage is normally finished living space, so garages and unfinished basements are usually left out. For a listing, sale or appraisal, use a professional measurement, such as an appraiser's, rather than a room-by-room estimate.
Measuring tips
- Measure twice, and round to the nearest inch.
- Measure closets, alcoves and bay windows as separate rows.
- Door openings are not counted in floor area.
- For circles and triangles, use the square footage calculator and add the result as a row.
Frequently asked questions
How do you calculate the square feet of a room?
Measure the length and the width of the floor in feet, then multiply the two numbers. A room 15 feet by 20 feet is 300 square feet. Measure wall to wall at floor level, round to the nearest inch, and turn inches into feet by dividing by 12 before you multiply.
How do you calculate the square footage of a house?
Find the square footage of each room, hallway and closet, then add them together. A 300 square foot living room, a 144 square foot bedroom and a 120 square foot kitchen total 564 square feet. For a listing, sale or appraisal, use a professional measurement, such as an appraiser's, rather than a room-by-room estimate.
How do you measure a room that is not a rectangle?
Split the floor into rectangles, measure each one, and add them. Measure an alcove or a bay as its own small rectangle and add it as a row. For an area you will not cover, such as a stair opening or a built-in cabinet, add it as a row and tick Subtract so the calculator removes it.
How do you find the square footage of a 2 story house?
Add the floor area of each story. If the first floor is 1,200 square feet and the second is 1,000 square feet, the house has 2,200 square feet. Homes are usually listed with finished living space only, so garages, unfinished basements and open-to-below areas are normally left out of that number.
What is the square footage of a 20x20 room?
A 20 by 20 foot room is 400 square feet, because 20 x 20 = 400. That is about 44.44 square yards or 37.16 square meters. If you are buying flooring for it, plan on about 440 square feet once you add 10 percent for cuts and waste.