Convert Area

An acre was a day of ploughing

It is the area one man with one ox could plough in a day: a furlong long by a chain wide, 4,047 square metres. Not a round number in any modern unit, because it was never derived from one.

A hectare, by contrast, is exactly 10,000 square metres — a square 100 m on a side — and is about two and a half acres. Most of the world measures land in hectares; the English-speaking world largely still does not.

Squaring a unit squares the conversion

This is where people go wrong. A metre is about 3.28 feet, so it is tempting to expect a square metre to be about 3.28 square feet. It is 10.76 — 3.28 squared.

The same trap applies in reverse and gets worse with bigger units: a square mile is not 1,609 square metres but about 2.6 million of them. If a figure looks implausibly small, this is almost always why.

Floor area is measured differently by different people

The arithmetic here is exact; what counts as the area rarely is. Estate agents, architects and tax authorities each measure a building to their own standard — some include internal walls, some the space taken by stairwells, some balconies at half value.

So two honest figures for the same flat can differ by ten per cent before any conversion happens. Convert the number you were given; do not assume it means the same thing as the one you are comparing it against.

Nothing is sent anywhere

Every conversion on this page is arithmetic done in your own browser. No request is made, nothing is stored between visits, and the page keeps working with the connection switched off — which is a reasonable way to check the claim.