How do you calculate square footage?

Multiply the room's length by its width. For example, a 12 ft by 10 ft room is 12 × 10 = 120 square feet. For an L-shaped room, split it into two rectangles and add their areas.

How do I measure an L-shaped room?

Split the room into two rectangles, calculate each one's area (length × width), and add the two results together. The calculator does this for you.

Why do I need square footage for flooring or paint?

Contractors and stores price materials per square foot (flooring, tile, carpet) or per gallon of coverage (paint). Knowing your area lets you buy the right amount and compare quotes.

Square Footage Calculator — Calculate Any Room's Area

Published: January 10, 2026

Enter a room's dimensions to get its square footage and square meters instantly. Works for rectangles and L-shaped rooms, in feet or meters. No sign-up, no data stored.

Quick answer: Square footage = length × width. A 12×12 room is 144 sq ft; 1 sq meter = 10.764 sq ft. For L-shaped rooms, add the area of each rectangle.

Measure the room length and width, then multiply: sq ft = length × width.

Room shape

Units

Length (ft)

Width (ft)

Area

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Square feet

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Square meters

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Perimeter

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Sq ft per meter

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How square footage is calculated

The math is simple and exact — there are no assumptions to adjust for:

Rectangle: area = length × width. Example: a 12 ft × 10 ft room = 120 sq ft.
L-shape: split it into two rectangles, calculate each, and add them. Example: (10 × 8) + (6 × 4) = 80 + 24 = 104 sq ft.
Conversion: 1 square meter = 10.764 square feet. We show both so you can order materials sold in either unit.

For flooring, tile, and carpet, always add 5–10% waste to your area before ordering (more for diagonal or patterned layouts). This calculator gives the clean area; add waste yourself or use our material calculators.

Worked example: A 12 ft × 10 ft bedroom is 120 square feet (12 × 10). In meters that's about 11.15 m² (120 ÷ 10.764).

Square footage reference chart

Common room sizes and their exact areas — no calculator needed.

Room (ft × ft)	Square feet	Square meters
8 × 10	80	7.4
10 × 10	100	9.3
10 × 12	120	11.1
12 × 12	144	13.4
12 × 15	180	16.7
14 × 16	224	20.8
16 × 20	320	29.7

Last updated: October 2026 · Values are exact math (length × width), 1 m² = 10.764 sq ft.

Square footage FAQ

How do I calculate square footage?

Multiply length by width. A 12 ft by 10 ft room is 12 × 10 = 120 sq ft. For L-shaped rooms, split into two rectangles and add their areas.

How many square feet is a 12×12 room?

144 sq ft (12 × 12 = 144). That's about 13.4 square meters.

What's the difference between square feet and square meters?

One square meter equals 10.764 square feet. Divide square feet by 10.764 to get square meters; multiply by 10.764 to go the other way.

Do I add waste for flooring or tile?

Yes — add 5–10% for straight layouts, and 15–20% for diagonal or patterned layouts. This covers cuts, mistakes, and future repairs.

What counts as square footage for a home?

Typically the finished, heated living area — measured from the outside of exterior walls. Unfinished basements, garages, and attics usually don't count. Check your local appraisal rules for listings.

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