Acre Calculator
Enter a lot’s length and width in feet, or a figure in acres, and the acre calculator gives the size in acres, hectares, sq ft, m², square yards and square miles. The factors are exact, so 1 acre reads 43,560 sq ft. For older US deeds you can pick the US survey acre, and regional units such as guntha and bigha are built in with their sources.
Acre calculator
Type 1,200 or 5.75; a comma before three digits groups thousands.
- Result
- 0.40468564224 ha
- Accuracy
- Exact
1 acre = 0.40468564224 ha exactly.
In other units
- 4,046.8564224 m² (exact)
- ≈ 0.0040 km²
- 1 acre (exact)
- 43,560 sq ft (exact)
- 4,840 sq yd (exact)
- 0.0015625 sq mi (exact)
Conversion factor
- 1 acre = 0.40468564224 ha (exact)
- 1 ha ≈ 2.4710538 acres
How this was calculated
- acres = m² ÷ 4,046.8564224
- ha = m² ÷ 10,000
- acres = sq ft ÷ 43,560
- Result = value × (size of 1 “from” unit) ÷ (size of 1 “to” unit), worked out exactly
- From length × width: area = length × width
- Regional units use the size their source states for the region you pick
- Hectares (ha) = 1 acre × 0.40468564224 ha/acre = 0.40468564224 ha (exact)
How the calculator works it out
The acre
An international acre is 43,560 sq ft. With 1 ft = 0.3048 m, that is 4,046.8564224 m², exactly.
Lot from its sides
Choose “Length × width”, type the two sides, and the calculator multiplies them and divides by 4,046.8564224 m² per acre.
Any unit to any unit
Every conversion goes through square meters with exact factors: 1 ha = 10,000 m², 1 sq mi = 640 acres = 2,589,988.110336 m².
Exact or rounded
Results that end within 12 decimals are shown in full and marked exact; the rest are rounded to the decimals you choose and shown with ≈.
How big is an acre
An acre is 43,560 sq ft, 4,840 sq yd or 4,046.8564224 m², a little over 40 % of a hectare. The traditional shape is a strip one furlong long and one chain wide: 660 × 66 ft. Any shape with the same area is an acre too; a square acre is about 208.7 ft on each side.
Lot size from length and width in feet
Multiply the length by the width to get square feet, then divide by 43,560. A lot 100 × 200 ft is 20,000 sq ft ÷ 43,560 ≈ 0.4591 acre. In square meters it is 1,858.0608 m², which is 0.18580608 ha, both exact.
If the lot is not a rectangle, measure its sides and a diagonal and use the plot area calculator, which splits the shape into triangles.
Acres to hectares
Multiply acres by 0.40468564224 to get hectares: 5 acres is 2.0234282112 ha, exactly. Going the other way, 1 ha ≈ 2.4711 acres. For fields measured in meters and per-hectare figures, the hectare calculator starts from hectares.
Worked examples
A lot 100 × 200 ft is 20,000 sq ft, ≈ 0.4591 acre and 0.18580608 ha.
In meters, a plot 50 × 80 m is 4,000 m² = 0.4 ha exactly, and 4,000 ÷ 4,046.8564224 ≈ 0.9884 acre.
5 acres × 0.40468564224 = 2.0234282112 ha, exact.
Acres in guntha, bigha and other regional units
| Units in 1 acre | 1 unit in sq ft | Source | |
|---|---|---|---|
| Guntha, Gujarat | 40 | 1,089 | Department of Land Resources |
| Cent, Kerala | 100 | 435.6 | Department of Land Resources |
| Decimal, Bihar | 100 | 435.6 | Department of Land Resources, Revenue & Land Reforms Department |
| Kanal, Haryana | 8 | 5,445 | Revenue Department, Department of Land Resources |
| Bigha, Haryana (pre-settlement) | ≈ 4.8001 | ≈ 9,074.79 | Revenue Department |
| Bigha, Assam | 3.025 | 14,400 | Department of Land Resources |
| Bigha, Nepal (Terai) | ≈ 0.5975 | 72,900 | Survey Department |
Regional units by region, with sources
The guntha, cent and bigha figures in the table above come from those sources. Sizes of regional units differ by state and district and have changed over time; your land record is the authority.
Each regional figure comes from the source named in the calculator: state revenue departments, the Government of India’s Glossary of Revenue Terms, the Punjab Settlement Manual, Nepal’s Survey Department and Bangladesh’s Ministry of Land. Rows backed only by secondary sources such as Wikipedia or property portals are marked unverified and name their source. Where sources disagree on one unit in one region, each figure is listed as its own labelled option rather than one being picked for you. If your record gives a different size, pick “Custom size” and type it in.
Regional units covered
Farmland quoted in acres is often recorded in guntha, cent or bigha as well; the hectare calculator page lists every region the calculator knows for each of these units. Built in: aana, ankanam, bigha, biswa, biswansi, cent, chatak, daam, decimal, dhur, dhurki, ganda, ghumaon, ground, guntha, jareeb, kanal, kani, kara, katha, killa, kranta, lessa, marla, murabba, nali, ojutangsho, paisa, ropani, sarsai, til, across India, Pakistan, Nepal and Bangladesh. Units and regions not listed have no source we could cite, so they are left out: for those, and whenever your land record gives a different size, pick “Custom size” and type the size of one unit.
US survey acre vs international acre
Older US deeds and surveys may use the US survey foot, defined as 1200/3937 m. An acre of 43,560 US survey sq ft is 62,726,400,000/15,499,969 m², about 4,046.8726 m². That is about 4 parts per million larger than the international acre: 1,000 survey acres ≈ 1,000.004 international acres, about 16.19 m² more.
NIST and NOAA’s National Geodetic Survey deprecated the US survey foot from January 1, 2023, in favour of the international foot of exactly 0.3048 m (Federal Register notice of October 5, 2020). Pick “US survey acres” in the calculator only when your document uses them.
Acres to square feet, square meters and hectares
| Square feet | Square meters | Hectares | |
|---|---|---|---|
| 0.1 acres | 4,356 | 404.68564224 | 0.040468564224 |
| 0.25 acres | 10,890 | 1,011.7141056 | 0.10117141056 |
| 0.5 acres | 21,780 | 2,023.4282112 | 0.20234282112 |
| 0.75 acres | 32,670 | 3,035.1423168 | 0.30351423168 |
| 1 acre | 43,560 | 4,046.8564224 | 0.40468564224 |
| 2 acres | 87,120 | 8,093.7128448 | 0.80937128448 |
| 2.5 acres | 108,900 | 10,117.141056 | 1.0117141056 |
| 5 acres | 217,800 | 20,234.282112 | 2.0234282112 |
| 7.5 acres | 326,700 | 30,351.423168 | 3.0351423168 |
| 10 acres | 435,600 | 40,468.564224 | 4.0468564224 |
Frequently asked questions
How many square feet are in an acre?
43,560 sq ft, exactly. That is also 4,840 sq yd and 4,046.8564224 m².
How do I convert acres to hectares?
Multiply by 0.40468564224. 1 acre ≈ 0.4047 ha and 5 acres = 2.0234282112 ha. To go from hectares to acres, divide by the same number.
How do I find the acreage of a rectangular lot?
Multiply length by width in feet and divide by 43,560. A 100 × 200 ft lot is 20,000 sq ft, about 0.4591 acre. With sides in meters, divide the m² by 4,046.8564224.
How many guntha or bigha are in an acre?
It depends on the region. Gujarat’s guntha is 1/40 acre according to the Glossary of Revenue Terms, so 40 guntha make an acre; bigha sizes differ widely. Pick the unit and region in the calculator to see the figure and its source.
What is a US survey acre?
An acre measured in US survey feet (1200/3937 m each), used in older US deeds and surveys. It is about 4 parts per million larger than the international acre, about 4,046.8726 m².
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