Land Area Converter (acre, hectare, pyeong)

Understanding the land area converter — concept and principle

Land is measured in acres in the US and UK, in hectares in most of the world, and in pyeong (평), danbo (단보) and jeongbo (정보) in older Korean and Japanese documents and in everyday Korean conversation. Use this converter to compare a farm listing, read an old deed, check the size of a plot abroad or translate "300 pyeong" into square metres.

1 acre = 0.405 ha ≈ 1,224 pyeong; 1 ha = 3,025 pyeong exactly.

How it is calculated

Every unit is converted into hectares (ha), then into the target unit:

1 ha = 10,000 m²; 1 km² = 100 ha
1 acre (international) = 43,560 ft² = 4,046.8564224 m²
1 ft² = 0.09290304 m²
1 pyeong = 400/121 m² ≈ 3.3058 m²
1 danbo = 300 pyeong ≈ 991.74 m²; 1 jeongbo = 3,000 pyeong ≈ 0.9917 ha

Result = value × (ha in source unit) ÷ (ha in target unit).

The principle

Area units are squares of length units, so their factors come from squaring exact length definitions. The acre was historically one chain by one furlong (66 ft × 660 ft = 43,560 ft²); with the foot fixed at 0.3048 m in 1959, the acre is exactly 4,046.8564224 m². The pyeong is a square one gan (6 ja) on each side. Since 1 ja = 10/33 m, 1 gan = 20/11 m and 1 pyeong = (20/11)² = 400/121 m². This is why 1 ha is exactly 3,025 pyeong and why the quick rule "m² × 0.3025 = pyeong" works.

Worked example

Default inputs: value 1, from acres (international), to hectares.
1 acre = 4,046.8564224 m².
4,046.8564224 ÷ 10,000 = 0.4046856422 ha.
Other units: 43,560 ft², 4,046.856 ÷ 3.305785 ≈ 1,224.17 pyeong, about 4.08 danbo, 0.408 jeongbo.

How to read the result

For quick estimates: 1 ha ≈ 2.47 acres ≈ 3,025 pyeong; 1 acre ≈ 0.4 ha ≈ 1,224 pyeong; 1 danbo ≈ 1,000 m² and 1 jeongbo ≈ 1 ha. A football pitch of 105 × 68 m is about 0.71 ha or 1.76 acres. Korean land registers and listings use m² by law, so treat pyeong as a familiar reference, not the official figure.

Common mistakes

Converting with 3.3 m² per pyeong and expecting an exact result; the exact value is 3.3058 m².
Mixing up area and length: doubling the side of a square plot multiplies its area by four, not two.
Using the US survey acre for old American deeds without noting that it differs slightly (about 4 parts per million) from the international acre.

Keep in mind: The calculator gives exact unit conversions only. Legal land area is the surveyed figure in the official register, which may be rounded or measured differently. Use it, not a converted estimate, for contracts, taxes or permits.

Frequently asked questions

How many acres are in a hectare?

1 ha = 2.471053815 acres.

How many pyeong is 1 hectare?

Exactly 3,025 pyeong.

How many square metres is 300 pyeong?

300 × 400/121 ≈ 991.7 m², which is also 1 danbo.

How do I convert m² to pyeong quickly?

Multiply m² by 0.3025. For example, 84 m² × 0.3025 ≈ 25.4 pyeong.

Sources: NIST Special Publication 811 (2008), Appendix B · NIST Handbook 44, Appendix C, General Tables of Units of Measurement

Checked 8 Nov 2026. Factors from the SI Brochure (BIPM, 9th ed.) and NIST Special Publication 811 (2008), Appendix B.