Question 1

How do I calculate the square footage of a room?

Accepted Answer

Measure the length and the width of the room in feet, then multiply them together: length × width = square footage. A room that is 12 feet long and 12 feet wide is 12 × 12 = 144 square feet. Measure at the widest points, and if your tape gives inches, either enter the unit as inches above or divide inches by 12 to get feet.

Question 2

How many square feet are in a 12×12 room?

Accepted Answer

144 square feet. 12 × 12 = 144. In metric that is about 13.38 square metres, and in square yards it is exactly 16. A 12×12 room is a typical medium bedroom size in US homes.

Question 3

How do I measure an L-shaped room?

Accepted Answer

Split the L into two rectangles, measure each one, and add the two areas together. For example, a room that is 16 × 12 with a 6 × 8 alcove is (16 × 12) + (6 × 8) = 192 + 48 = 240 square feet. This calculator lets you add both rectangles as separate rows and totals them for you. Draw a quick sketch first — it makes splitting the shape much easier.

Question 4

How do I convert square feet to square metres?

Accepted Answer

Multiply square feet by 0.092903. For example, 144 sq ft × 0.092903 = 13.38 sq m. To go the other way, multiply square metres by 10.7639: a 12 sq m room is 12 × 10.7639 = 129.17 sq ft. This calculator shows both units on every result, so you never have to convert by hand.

Question 5

Does square footage include bathrooms, closets and hallways?

Accepted Answer

It depends on what the number is for. For flooring or paint, include every area you are actually covering — closets and hallways included, measured separately and added up. For real-estate listings in the US, the quoted square footage (often called GLA, gross living area) generally counts finished, heated above-ground living space, and typically excludes garages, unfinished basements and unheated porches; local rules and appraisal standards vary, so a listing figure and a flooring figure for the same home can legitimately differ.

Question 6

How much extra material should I order for waste?

Accepted Answer

A common allowance is 10% extra for straight-lay flooring and standard tile, because of cuts, breakages and mistakes; diagonal patterns and small, cut-heavy rooms often need 15%. Add your allowance in the calculator above and order for the 'including waste' total rather than the bare area. Keep a few spare pieces afterwards for future repairs.

Question 7

How do I find the square footage of a circle or triangle?

Accepted Answer

For a circle, measure the radius (centre to edge) and use π × radius² — a round rug or patio with a 10 ft radius is about 314.16 sq ft. For a triangle, use base × height ÷ 2, where the height is the perpendicular distance from the base to the opposite corner — a 10 ft base with an 8 ft height is 40 sq ft. Both shapes are built into the calculator above.

Question 8

Is my data private?

Accepted Answer

Yes. The calculator runs entirely in your web browser. The measurements you type are never sent to a server, stored, or shared — close the tab and they are gone.

Room size (ft)	Square feet	Square metres	Square yards
10 × 10	100.00	9.29	11.11
10 × 12	120.00	11.15	13.33
12 × 12	144.00	13.38	16.00
12 × 14	168.00	15.61	18.67
12 × 16	192.00	17.84	21.33
14 × 16	224.00	20.81	24.89
16 × 20	320.00	29.73	35.56
20 × 20	400.00	37.16	44.44

Square Footage Calculator

The example everyone starts with: a 12 × 12 room

Common room sizes in square feet

Gear up for the project

Common questions