How this instrument works
The are is pure metric invention: French Revolutionary reformers who drew up the metric system in 1795 defined it as a square exactly 10 metres on a side, 100 square metres, and named the hectare simply as a hundred ares stacked together. It never entered the SI proper but the International System still recognises it as accepted for use alongside SI units, specifically for measuring land, which is why European cadastral records and small European garden plots still quote area in ares to this day.
The cent has an entirely different pedigree. It is a hundredth of an acre, 40.468564224 square metres, and it survives almost exclusively in property transactions across Kerala, Tamil Nadu and parts of Andhra Pradesh — a leftover of British-era land survey practice that measured India in acres, later subdivided into a friendlier decimal unit for describing the smaller urban and suburban plots that dominate South Indian real estate. Neither unit shares any ancestry with the other; the arithmetic connecting them runs purely through their shared reference to the square metre.
That shared reference produces a small mathematical curiosity worth noticing: converting ares to cents and converting hectares to acres both use the identical multiplier, 2.47105381467. That is not a coincidence — a cent is exactly one hundredth of an acre and an are is exactly one hundredth of a hectare, so scaling both units down by the same factor of a hundred leaves the ratio between them completely unchanged.
- Enter the plot size into Ares (are); the field opens at 1, so you can watch the factor apply directly.
- Read the equivalent size from Cents (cent) beneath it, recalculated to eleven decimal places on every keystroke.
- Coming from a South Indian property listing in cents? Divide the cent figure by 2.47105381467 to get ares.
- Fractional plots convert cleanly too — enter 0.5 for half an are, or 25 for a plot a quarter-hectare in size.
Worked example — a 1-are plot listed for a metric buyer
A property agent in Kochi lists a residential plot as 2.47 cents in the local paper, but the buyer relocating from Germany is used to seeing land measured in ares on every deed she has ever signed. Enter 1 into Ares (are) and Cents (cent) reads 2.47105381467 — near enough to the advertised 2.47 cents that the two figures plainly describe the same patch of ground, with the tiny gap explained entirely by the local listing's own rounding.
Scaling up to a larger holding shows the same pattern: a 25-are smallholding, a quarter of a hectare, converts to 61.7763453668 cents, while a modest half-are garden plot comes to 1.23552690734 cents. Every one of those figures traces back to the same 100 m² are and the same 40.468564224 m² cent, so nothing is ever approximated along the way — only the final digits shown get rounded for display.
Questions
Why is 2.47105381467 the exact conversion factor?
It falls out of two independent definitions meeting at the square metre. An are is fixed at exactly 100 square metres by the 1795 metric decree. A cent is fixed at exactly 1/100 of an acre, and an acre — inherited from British land-survey practice — comes to 4046.8564224 square metres once the international yard is applied. Dividing 100 by 40.468564224 gives 2.47105381467, a ratio that never terminates because the acre's definition carries a factor of 11 that has no place in a base-ten decimal.
Where is the cent actually used as a land unit?
Primarily in Kerala, and to a lesser extent in Tamil Nadu, Andhra Pradesh and parts of Karnataka, where real estate listings, land registration documents and casual conversation about property size all default to cents rather than square metres or acres. A typical urban residential plot in the region might run 5 to 10 cents, while agricultural land is more often quoted in acres, with the cent reserved for describing smaller, subdivided parcels.
Is the are used much outside continental Europe?
Rarely as a headline unit, though it survives in official land records across several countries that adopted French metric conventions early, including parts of Francophone Africa and Southeast Asia. Most English-speaking countries skip straight from square metres to hectares without using the are in between, which is one reason it can feel like an obscure unit even though it sits directly between those two far more familiar ones.
How many cents make one acre?
Exactly 100, by definition — that is the entire point of the unit. An acre measures 4046.8564224 square metres, so one cent is 40.468564224 square metres, or roughly 435.6 square feet. A plot advertised at 100 cents is therefore precisely one acre, and South Indian property listings routinely use that round-number relationship to help buyers translate between the smaller cent figure and the more internationally familiar acre.
Does 'cent' here have anything to do with monetary cents?
No connection at all beyond the shared word for 'hundredth,' which comes from the same Latin root, centum. The monetary cent is 1/100 of a dollar or similar currency unit; the land cent is 1/100 of an acre. Both names describe the same idea of decimal subdivision applied to entirely different quantities, and the coincidence of naming has nothing to do with either unit's actual definition.
Can I convert directly from square metres to cents without going through ares?
Yes — divide the square metre figure by 40.468564224 to get cents directly, since that is the exact area of one cent. Going through ares first, as this page does, simply reflects how many South Asian land records and international buyers actually think about the numbers: a deed quoted in ares divides cleanly by that same 40.468564224 m² reference once you know one are equals exactly 100 square metres.