Area Converter
Convert area between mm², cm², m², hectares, km², in², ft², yd², acres and mi² — all at once.
mm²
1,000,000
cm²
10,000
m²
1
ha (hectare)
0.0001
km²
1.0000e-6
in²
1,550.0031
ft²
10.76391
yd²
1.19599
acre
0.00024711
mi²
3.8610e-7
How to use
- Type an area value.
- Pick the unit you entered it in.
- Read the value in every other unit and copy whichever you need.
About this tool
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Convert between ten area units — square millimetres through square kilometres, square inches through square miles, plus hectares and acres — with every other unit updating as you type. All the factors are exact rather than rounded, because these units are defined exactly: an inch is 2.54 centimetres by international agreement, so a square foot is precisely 0.09290304 square metres, and every conversion here goes through square metres as a single multiplication, so a value converted out and back comes home unchanged. The odd-looking numbers are the historical definitions showing through: an acre is 4,840 square yards, a square mile is exactly 640 acres — the section of the American survey grid — while a hectare is simply a 100-metre square.
Frequently asked questions
How big is an acre in square feet and square metres?
1 acre = 43,560 ft² = 4,046.8564224 m² ≈ 0.4047 hectares. It's the area of a square about 208.7 ft (63.6 m) on each side.
How do hectares and acres relate?
1 hectare = 10,000 m² ≈ 2.4711 acres, and 1 acre ≈ 0.4047 hectares. A hectare is the area of a 100 m × 100 m square.
How many square feet are in a square metre?
1 m² ≈ 10.7639 ft², and 1 ft² = 0.09290304 m². To go the other way, divide square feet by about 10.764 to get square metres.
How large is a square mile?
1 mi² = 640 acres = 2.589988110336 km² ≈ 259 hectares. A square kilometre, by comparison, is about 0.386 mi².
Are the conversion factors rounded?
No, they are exact. The imperial units are defined against the metre by international agreement — an inch is exactly 2.54 cm — so a square foot is precisely 0.09290304 m² and an acre precisely 4046.8564224 m². Converting out and back returns the number you started with.
Why are the imperial numbers so awkward?
Because they were never designed around ten. An acre is 4,840 square yards, historically a day's ploughing; a square mile is exactly 640 acres, the section of the American survey grid. The metric units are the tidy ones — a hectare is simply a square 100 metres on a side.
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