Square Footage Chart

Most square footage questions come down to looking something up. How big is a 12 by 12 room, how many square feet in an acre, what a 30 by 40 building works out to. The charts below cover the common ones, and the calculator handles anything that isn't on the list.

Room size chart

Multiply the two dimensions and you have the square footage. Metric is included because floor plans and imported furniture specs often use it.

Room size	Square feet	Square meters
8 x 8 ft	64 sq ft	5.9 m2
8 x 10 ft	80 sq ft	7.4 m2
9 x 9 ft	81 sq ft	7.5 m2
10 x 10 ft	100 sq ft	9.3 m2
10 x 12 ft	120 sq ft	11.1 m2
11 x 12 ft	132 sq ft	12.3 m2
10 x 14 ft	140 sq ft	13.0 m2
12 x 12 ft	144 sq ft	13.4 m2
12 x 14 ft	168 sq ft	15.6 m2
13 x 13 ft	169 sq ft	15.7 m2
12 x 16 ft	192 sq ft	17.8 m2
14 x 14 ft	196 sq ft	18.2 m2
14 x 16 ft	224 sq ft	20.8 m2
15 x 15 ft	225 sq ft	20.9 m2
16 x 16 ft	256 sq ft	23.8 m2
16 x 20 ft	320 sq ft	29.7 m2
18 x 18 ft	324 sq ft	30.1 m2
20 x 20 ft	400 sq ft	37.2 m2
20 x 24 ft	480 sq ft	44.6 m2
24 x 24 ft	576 sq ft	53.5 m2
20 x 30 ft	600 sq ft	55.7 m2

For why rooms land on these sizes and what each one is typically used for, see standard room sizes.

What the code says a room has to be

There is a floor under these numbers. The residential code requires habitable rooms to be at least 70 square feet and at least 7 feet in any horizontal dimension, under section R304, with kitchens exempt from both. Section R305 sets a minimum ceiling height of 7 feet, with lower allowances for bathrooms and some basement spaces.

So a 7 by 10 room at 70 square feet is the smallest legal bedroom, and anything narrower than 7 feet doesn't qualify as habitable space no matter how long it is. That matters for square footage counting as much as for building: space that isn't habitable generally isn't living area, which what counts as square footage goes through in detail.

Garage and building size chart

Building size	Square feet	Typical use
12 x 22 ft	264 sq ft	Single-car garage
14 x 24 ft	336 sq ft	Single-car garage with storage
20 x 20 ft	400 sq ft	Compact two-car garage
24 x 24 ft	576 sq ft	Standard two-car garage
24 x 30 ft	720 sq ft	Two-car garage with a shop bay
30 x 30 ft	900 sq ft	Three-car garage, small shop
30 x 40 ft	1,200 sq ft	Pole barn, workshop
40 x 40 ft	1,600 sq ft	Large shop
40 x 60 ft	2,400 sq ft	Barn, light industrial
50 x 100 ft	5,000 sq ft	Commercial bay

A garage is measured and priced like any other rectangle, but it does not count toward a home's living area. Does a garage count as square footage explains why, including the attached versus detached question.

Unit conversion chart

To convert	Into	Do this
Square feet	Square inches	Multiply by 144
Square feet	Square yards	Divide by 9
Square feet	Square meters	Multiply by 0.092903
Square feet	Acres	Divide by 43,560
Square feet	Roofing squares	Divide by 100
Square inches	Square feet	Divide by 144
Square yards	Square feet	Multiply by 9
Square meters	Square feet	Multiply by 10.7639
Acres	Square feet	Multiply by 43,560
Hectares	Square feet	Multiply by 107,639

The area converter handles all of these at once, plus square miles and square kilometers. The square foot to square meter factor is exact rather than rounded, because the foot itself is defined as exactly 0.3048 meters, which makes a square foot exactly 0.09290304 square meters.

The squaring step is where people slip. A yard is 3 feet, but a square yard is 9 square feet. A meter is about 3.28 feet, and a square meter is 10.76 square feet.

Square feet to acres chart

Square feet	Acres
1,000 sq ft	0.023 acres
2,500 sq ft	0.057 acres
5,000 sq ft	0.115 acres
7,500 sq ft	0.172 acres
10,000 sq ft	0.230 acres
10,890 sq ft	0.25 acres
21,780 sq ft	0.5 acres
43,560 sq ft	1 acre
87,120 sq ft	2 acres
217,800 sq ft	5 acres

An acre is 43,560 square feet, which is a strange number because it comes from an old measure of the land a team of oxen could plow in a day rather than from anything geometric. The acres converter handles the decimals.

What a whole-house square footage feels like

Home size	Rough layout
800 sq ft	One bedroom, open living and kitchen
1,200 sq ft	Two or three bedrooms, one and a half baths
1,600 sq ft	Three bedrooms, two baths
2,000 sq ft	Three or four bedrooms, two baths, separate dining
2,600 sq ft	Four bedrooms, two and a half baths, around the average for a new US home
3,500 sq ft	Five bedrooms or a large primary suite plus bonus room

These are rules of thumb rather than rules. Layout efficiency changes what a number feels like: 1,600 square feet on one floor lives larger than the same area split over three levels with two staircases. Average square footage of a house has the actual data and how it has changed over time.

How to use these charts

Ordering materials. Take the area from the chart, add the waste factor for the material, and buy that. A 12 by 16 room at 192 square feet needs about 211 square feet of hardwood at 10 percent waste.

Sizing equipment. Cooling and heating are sized off the area you're conditioning, not the whole floor plan. The BTU calculator applies the ENERGY STAR chart to your number.

Comparing listings. Check that both listings measure the same way before dividing into the price. The price per square foot calculator covers what makes two figures comparable.

Anything not on the chart. Multiply it yourself, or use the rectangle calculator. For an L-shape or a curved edge, the irregular shape calculator breaks it into pieces.

Frequently asked questions

How many square feet is a 12x12 room?

144 square feet, since 12 x 12 = 144. In metric that's 13.4 square meters.

How many square feet is a 10x10 room?

100 square feet, or 9.3 square meters. It's the size of a standard small bedroom or a large storage unit.

How many square feet is a 15x15 room?

225 square feet, which is 20.9 square meters. A 14 by 16 room is close at 224 square feet.

How many square feet is a 10x12 room?

120 square feet, or 11.1 square meters. That's a common bedroom size and comfortably over the 70 square foot code minimum for a habitable room.

How many square feet is a 20x20 room?

400 square feet. The same dimensions make a compact two-car garage, while 24 by 24 at 576 square feet is the more usual size.

How many square feet is a 30x40 building?

1,200 square feet, a common pole barn and workshop size. A 40 by 60 building is 2,400 square feet.

How many square feet are in a square of roofing?

100 square feet. Roofers order by the square, so a 2,400 square foot roof is 24 squares before waste. The roof calculator works it out including pitch.

How big is 1,000 square feet?

About the size of a two-bedroom apartment, or a rectangle roughly 25 by 40 feet. It's 93 square meters, or 0.023 acres.

What is the smallest a room can legally be?

Under the residential code, a habitable room has to be at least 70 square feet with no horizontal dimension under 7 feet, and a ceiling at least 7 feet high. Kitchens are exempt from the floor area and width rules.