Hectares to cm²
One hectare is 100,000,000 cm², and this shows the working rather than just the answer. Nothing you type here leaves your browser — it is worked out on your own device, so there is nothing to send and nothing to log.
The factor
One hectare is 100,000,000 cm². That is the whole of the conversion: multiply by it, and nothing else happens.
And it is exact
Not rounded, not measured, not a convention that might be revised. The factor above is the definition, so an answer from it is as exact as the number you typed.
The hectare is 10,000 m², or a square 100 m on a side.
The number in your head
Most people use 99,999,999.999999985099 for this, which is the factor to three significant figures. It is low by 1.490116e-14% — 1.490116e-13 cm² too few in every thousand, and 1.490116e-12 in every ten thousand.
Going the other way
The reverse is not this sum backwards in your head. It is a different factor, 1.000000e-08, and dividing by one is not the same as multiplying by a rounded version of the other.
That one is short enough to write down exactly, which is why the conversion feels easier in this direction than the other.
How many of those decimals mean anything
The box above will give you ten decimal places because it can. Whether they mean anything is decided by your measurement, not by the arithmetic.
If you measured to the nearest hectare, your figure is already uncertain by half of one — so the answer is uncertain by about 50,000,000 cm², and every digit past that is decoration. Quoting 123,456,000.00000001 when you measured with a tape is claiming a precision the tape never had.
Where these two sit
Hectares and cm² both measure area, which is why they can be converted at all. A conversion between families — a length into a weight — is not a conversion, it is a question with a missing quantity in it.
The unit converter pairs hectares with acres rather than with cm², because that is the conversion people ask for most. This page exists because a good many ask for this one instead.
Other conversions from hectares
acres · ft² · m² · km² · mi² · yd²