Why area units are so confusing
Few measurements come in as many incompatible flavours as area. A builder quotes a flat in square feet. A property deed lists the plot in acres. A farmer describes the same land in guntha or bigha. A government map uses hectares. Each unit made sense for the people who invented it, but together they’re a recipe for expensive mistakes — especially in property and agriculture, where getting a conversion wrong can mean paying for land you didn’t get.
The Area Converter takes the arithmetic out of it: type a value into any unit and every other unit updates instantly. This guide explains what the units actually mean so the numbers make sense.
The metric units
Metric area units are the easiest because they scale by powers of ten and a hundred.
- Square metre (m²) — the base SI unit, a 1 m × 1 m square.
- Square centimetre (cm²) — 0.0001 m². There are 10,000 cm² in a square metre (not 100 — area scales as the square of length).
- Square kilometre (km²) — 1,000,000 m². Used for cities, districts, and regions.
- Hectare (ha) — 10,000 m², a 100 m × 100 m square. The standard unit for farmland and land area worldwide.
- Are — 100 m². A hectare is 100 ares; the name “hectare” literally means “hundred ares.”
A common trap: doubling a length quadruples the area. A 2 m × 2 m square (4 m²) is four times a 1 m × 1 m square, not twice. Area always scales as length squared.
The imperial units
- Square foot (ft²) — 0.092903 m². The default for interiors and built-up area in the US, UK, and India.
- Square yard (yd²) — 9 ft², or about 0.8361 m². Common for plots in parts of India (“gaj”).
- Acre — 43,560 ft², or about 4046.86 m². Historically the area a yoke of oxen could plough in a day, which is why it isn’t a round number.
- Square mile (mi²) — 640 acres, about 2.59 km².
The Indian land units
This is where the Area Converter earns its keep, because these units appear constantly in Indian property and farming and rarely in generic converters.
Guntha
A guntha is 1089 square feet (about 101.17 m²). It’s a clean sub-division of the acre: there are exactly 40 guntha in an acre. Guntha is widely used in Maharashtra, Karnataka, and other states for farm and plot sizes.
Cent
A cent is 1/100 of an acre, about 40.47 m². It’s common in South India, particularly Tamil Nadu, Kerala, and Andhra Pradesh. One hundred cents make an acre — easy to remember.
Bigha
Bigha is the tricky one. It is a traditional unit with no single national definition, and its size varies dramatically by state.
| Region | Approx. 1 bigha | Notes |
|---|---|---|
| West Bengal | ≈ 1,338 m² | Smaller bigha |
| North India (pucca) | ≈ 2,529 m² | 3025 square yards |
| Rajasthan (pucca) | ≈ 2,500–2,900 m² | Varies locally |
Because of this variation, the Area Converter uses the pucca bigha of 3025 square yards (≈ 2529.29 m²) and labels it clearly. For any legal or official transaction, always confirm the bigha definition used in that specific district — never assume.
Conversions worth memorising
A handful of relationships cover most real situations:
- 1 acre = 43,560 ft² = 4046.86 m² = 40 guntha = 100 cent
- 1 hectare = 10,000 m² ≈ 2.47 acres
- 1 guntha = 1089 ft² ≈ 101.17 m²
- 1 square yard = 9 ft²
If you know these, you can sanity-check almost any conversion the tool gives you.
How the converter stays accurate
Behind the scenes, every unit is defined by an exact factor relating it to the square metre. To convert, the tool multiplies your value by the source unit’s factor to get square metres, then divides by the target unit’s factor. Results are shown to eight significant figures. Because the underlying factors are exact (for instance, 1 ft² = 0.09290304 m² exactly), the conversions are exact too — only the display is rounded.
Practical advice
- For property deals, convert everything to one unit (square metres or square feet) before comparing listings, so you’re not fooled by unit-switching.
- For farmland, hectares and acres are the safest common ground; convert guntha and bigha into one of them for planning.
- For anything legal, confirm local definitions — especially for bigha — and keep the exact figures, not rounded ones.
Try it now with the Area Converter. If you also deal with distances and lengths, the Length Converter guide covers the same ideas for linear measurement.