Area Converter

What this converter answers

What an area is in other units, and whether that answer is exact. Enter an area, or a room’s length and width, and you get it in square millimeters, centimeters, meters and kilometers, square inches, feet, yards and miles, acres and hectares at once. The steps show where each factor comes from, and the tiles put the size in terms you can picture: the side of a square with the same area, a fraction of an acre, and American football fields.

How to use it

• Start from: An area when you already have the number, or Room size (length × width) when you have the measurements of a rectangle.
• Area: the number, such as 1,850 or 0.25, in the unit you pick under From. You can also type or paste the unit after it, as in 1,850 sq ft, 85 m² or 2.5 acres: From switches to that unit and the line under the box shows how it was read. A length such as 12 ft is read as 12 ft², with a note asking whether you meant square feet. Two sides such as 12 x 10 go under Room size.
• Length and Width (room size): each side has its own unit. In feet you can type 14 ft 6 in, 14' 6" or 14.5. If both sides use the same unit, changing the length’s unit changes the width’s too; the numbers stay as typed.
• To: the unit for the main result. Every other unit is listed in the table under it.
• Price (optional): a total price for the area, or a price per unit, chosen under Price is. You get the price per square foot, square meter, acre and more, and the total.
• Significant figures: Auto shows up to 12 significant figures, so exact values such as 0.09290304 appear in full. Choose fewer for a shorter answer.

The Try buttons load an acre in square feet, acres to hectares, an apartment in square meters, a room in feet and inches, and a flooring price per square meter. Each is worked through below.

How many square feet are in an acre?

Exactly 43,560. An acre is defined as 43,560 ft², which is 10 square chains of 66 ft, or a strip 66 ft wide and 660 ft (a furlong) long. Since the foot is exactly 0.3048 m, an acre is also exactly 4,046.8564224 m², or 0.40468564224 hectare.

A square acre measures about 208.71 ft (63.61 m) on each side, and a square mile holds exactly 640 acres (27,878,400 ft²). For lots smaller than an acre, the converter shows the fraction: 5,000 ft² is 0.114784205693 acre, which is exactly 1/8.712 of an acre.

Square feet to square meters (and back)

Multiply square feet by 0.09290304 to get square meters. That factor is exact, so every square-foot figure has an exact square-meter value. Going the other way, divide by 0.09290304, or multiply by about 10.7639: 85 m² is 914.93238542 ft².

Why area conversion factors are squared

A square foot is a square 1 ft on each side. Each side is 0.3048 m, so its area is 0.3048 m × 0.3048 m = 0.09290304 m². Every square unit works the same way: square the length factor.

This is why multiplying square feet by 0.3048, or square meters by 3.28, gives a wrong answer. 1,850 ft² × 0.3048 is 563.88, which isn’t the area in any unit, while the right answer is 171.870624 m². The steps under every result show the squared factor for the units you chose.

Area conversion formula

Each unit has a fixed size in square meters, $f$. To convert an area $x$ from one unit to another:

• $x_{\text{from}}$ is the area you have, $x_{\text{to}}$ the area in the new unit.
• $f$ is the unit’s size in square meters: 0.09290304 for a square foot, 10,000 for a hectare, 4,046.8564224 for an acre. For a square unit it is the length factor squared, $f = \ell^2$.

Worked example: 1,850 square feet in square meters

A house listing gives 1,850 ft². In square meters:

1. Square the length factor: 1 ft = 0.3048 m, so 1 ft² = 0.3048 m × 0.3048 m = 0.09290304 m².
2. Multiply: 1,850 × 0.09290304 = 171.870624 m². Both numbers are exact, so the result is exact.
3. In acres: 1,850 ÷ 43,560 = 0.0424701561065 acre, about 1/23.55 of an acre.
4. As a square: the side is √1,850 ≈ 43.01 ft, or √171.870624 ≈ 13.11 m.

The table under the result gives the same area as 266,400 in², 205.555555556 yd² and 0.0171870624 ha. A listing would round it to 171.87 m².

Converting room dimensions to square feet or square meters

Multiply the length by the width in the same unit. Choose Room size (length × width) and enter each side with its unit; feet and inches are fine. For a room 14 ft 6 in by 11 ft 3 in:

1. Feet and inches to feet: 14 ft 6 in = 14 + 6 ÷ 12 = 14.5 ft, and 11 ft 3 in = 11.25 ft.
2. Area: 14.5 ft × 11.25 ft = 163.125 ft².
3. Square meters: 163.125 × 0.09290304 = 15.1548084 m², exact.

The sides don’t have to share a unit. A space 12 ft 6 in by 3.2 m is worked in meters: 12 ft 6 in = 150 in = 3.81 m, and 3.81 m × 3.2 m = 12.192 m², which is 131.233595801 ft². When inches don’t turn into a short decimal of a foot, as with 13 ft 4 in, the area is worked in square inches instead, so nothing is rounded before the last step.

The helper covers rectangles. For an L-shaped room, work out each rectangle and add the areas; for circles, triangles and other shapes, work out the area with an area calculator first and convert it here.

Acres vs hectares

A hectare is 10,000 m², a square 100 m on each side, and is the land unit in metric countries. An acre is smaller: 1 acre = 0.40468564224 ha exactly, and 1 ha ≈ 2.47105381467 acres. So 2.5 acres is 1.0117141056 ha, a little over one hectare.

Every value in the table is exact. The are, 100 m², is one hundredth of a hectare; choose it under From or To when a document uses it.

How big is an acre?

About three quarters of an American football field. The whole field, end zones included, is 360 ft × 160 ft = 57,600 ft², so an acre is 43,560 ÷ 57,600 = 75.625% of it. Between the goal lines the field is 300 ft × 160 ft = 48,000 ft², and an acre is about 91% of that. As a square, an acre is about 208.71 ft on each side; as a strip, 66 ft by 660 ft. The American football fields tile gives the same comparison for your own area.

Price per square foot vs price per square meter

Prices convert the other way round from areas. There are about 10.7639 ft² in 1 m², so a price per square meter is about 10.76 times the price per square foot. For example, flooring at $3.49 per ft² costs about $37.57 per m², and 1,850 ft² of it costs $6,456.50. Multiplying $3.49 by 0.09290304 instead gives $0.32, which is far too low to be a price per square meter.

Enter a Price and choose Price is: for the whole area, or per unit. The price table then lists the price per square foot, square yard, square meter, acre and hectare, with the total for your area.

Reading the result

• The headline is the area in the To unit, followed by the equation and whether it is exact or how it was rounded. For room sizes the equation starts from the sides.
• The factor line works both ways: in the example, 1 ft² = 0.09290304 m² exactly, and the reverse, 1 m² ≈ 10.7639104167 ft², is rounded.
• The tiles show a square with the same area (or, for a room, its sides in the other system), the area in acres or as a fraction, and the number of American football fields.
• How this was calculated shows the sides turned into one unit, the squared factor or the land-unit definitions, and the conversion with your numbers.
• The conversion table lists the area in every unit, grouped as metric, US customary and land units, each marked Exact or Rounded. Selecting a unit name, such as acres, makes it the main result, and Download CSV or Copy table exports every row.
• The price table (with a price) lists the price per unit in each unit and the total.
• Save for comparison keeps up to three conversions side by side, with the change in square meters from the first.
• Continue in links pass a room’s sides to the area and perimeter calculator (when both sides use one unit) and a floor-sized area to the flooring calculator as its total area, within this browser tab.

Common area conversion mistakes

• Using the length factor for an area. Square feet times 0.3048, or square meters times 3.28, is off by a factor of 3.28. Square the factor: 0.09290304 and 10.7639.
• Entering one side as the area. 12 ft is a length; a 12 ft × 10 ft room is 120 ft². If you type 12 ft in the Area box, the converter reads it as 12 ft² and asks whether that is what you meant.
• Reading 13 ft 4 in as 13.4 ft. Four inches is 0.333 ft. A 13 ft 4 in × 11 ft 9 in room is 156.666666667 ft², while 13.4 × 11.75 gives 157.45 ft², 0.5% too much. Type the feet and inches as they are.
• Rounding the sides before multiplying. Keep the full measurements and round only the final area.
• Mixing up hectares and acres. A hectare is about 2.47 acres, so land prices or yields per hectare look about 2.47 times larger than per acre.
• Dividing a price by the area factor. A price per unit area converts with the inverse factor, as the price section shows.

Assumptions and limitations

• The factors are the exact definitions: the international foot of 0.3048 m and the units built on it, the acre of 43,560 ft², the hectare of 10,000 m². Results are rounded only for display, to the significant figures you choose.
• Acres use the international foot. Older US land records based on the survey foot describe an acre about 4 parts per million larger, 4,046.872609874 m² instead of 4,046.8564224 m², a difference of about 0.016 m² per acre that matters only for surveying.
• A converted area can’t be more exact than the measurement. A room measured to the nearest inch has an area uncertain by roughly a square foot, however many digits the conversion shows.
• The room size helper multiplies two sides, so it assumes a rectangle with square corners.
• Areas must be 0 or more and at most 10¹⁵ in the unit typed. Each side must be greater than 0 and at most 1,000,000 in its unit.
• The price table converts a price as entered; it doesn’t add taxes, fees, waste or rounding to whole boxes.