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Square footage calculator

Multiply each room's length by its width in feet, then add the rooms up. Turn inches into feet first: 6 inches is 0.5 ft, so a 10 ft 6 in by 12 ft bedroom is 126 square feet. Keep the garage and any unfinished space on their own line. Add up a whole house and you'll usually land under the square footage on its appraisal. Nothing went wrong: the appraiser measures the house, and you measured the rooms. The rooms are what a remodel is priced on.

Length
Width
224 sq ft
Length
Width
137.5 sq ft
Length
Width
168 sq ft
Length
Width
110 sq ft
Length
Width
40 sq ft
Length
Width
400 sq ft

Finished living space

679.5 sq ft

63.1 m²

  • Other space (garage, unfinished)400 sq ft
  • All rooms1,079.5 sq ft
Start the free readiness assessment

How to calculate the square footage of a room

Measure the floor wall to wall, to the nearest inch. For the inches, divide by 12 and add the result to the feet: 3 inches is 0.25 ft, 9 inches is 0.75 ft.

A room that isn't a rectangle is a few rectangles. Draw the room, cut it into rectangles that don't overlap, and enter each one as its own row.

One L-shaped room is two rectangles: 168 + 48 = 216 sq ft

One L-shaped room is two rectangles: 168 + 48 = 216 sq ftAn L-shaped room split into two rectangles. The larger is 14 by 12 feet, which is 168 square feet. The smaller is 8 by 6 feet, which is 48 square feet. Together they make 216 square feet.14 × 12 ft168 sq ft8 × 6 ft48 sq ft14 ft12 ft8 ft6 ftCut here
All areas in square feet. The dashed gold line is the cut between the two rectangles.

The same area can be very different rooms. 300 square feet is 15 by 20 feet, 12 by 25 feet, or about 17 ft 4 in on each side.

Three rooms, each 300 sq ft

Three rooms, each 300 sq ftThree rectangles drawn to one scale, each 300 square feet: 15 by 20 feet, 12 by 25 feet, and about 17 feet 4 inches on each side.15 × 20 ft12 × 25 ft17 ft 4 inon each side
Drawn to one scale.

Why your total is smaller than the appraisal

An appraiser for a Fannie Mae mortgage has to follow the ANSI Z765-2021 standard, required since April 2022. Under it, the house is measured from the outside of its walls, so the walls, the halls and the closets are all in. The stairs count on the floor they come down from. The garage and unfinished space are left out, and a basement is reported separately. Fannie Mae now calls the main figure above-grade finished area, the number that used to be called gross living area.

Where you measure, and where an appraiser does

Where you measure, and where an appraiser doesA floor plan. The gold areas are the rooms, measured inside the walls, and they add up to the room total. The black outline is the outside of the walls. An appraiser measures to that line, so the walls, the hall and the stairs are included. The garage next to the house is outside the count.Black line: where an appraiser measuresLiving roomKitchenBathBedroomHallStairsGaragenot countedGold rooms: what you measure, inside the walls
Not to scale.

Price the work on the rooms you're changing

Take a room's total into the kitchen remodel cost calculator or the bathroom remodel cost calculator, or add rooms with the home addition cost calculator.

For flooring, order more than the room total to cover cuts. Carpet One suggests at least 5% to 10% extra, and 20% for carpet. Your installer will give you the figure for your material.

For the whole project, start the free readiness assessment. After the readiness questions about the project, the estimate asks for the square footage of what you're changing: the kitchen, the bathroom, the basement, the area getting new flooring. You get back a preliminary room-by-room estimate and the questions to settle before work begins. More free tools are on the tools page.

Questions people ask

How many square feet is a 12x12 room?

144 square feet. A 12x8 room is 96, a 20x20 room is 400, a 30x40 space is 1,200 and a 30x50 space is 1,500.

Does the square footage of a house include the second floor?

Yes. Every finished floor above ground counts. An opening to the floor below, like the open space over a two-story foyer, isn't counted on the upper floor.

How do I convert square feet to square meters?

Divide by 10.7639. 1,000 square feet is about 92.9 square meters. The calculator shows both.