This online calculator converts area between square kilometers (km²) and acres (ac). It uses exact, standards-based relationships: the international foot is defined as 0.3048 m exactly and an acre is 43,560 ft², which together fix 1 acre = 4046.8564224 m² and thus 1 km² = 247.105381467 ac.

Square Kilometers (km²) to Acres (ac) Converter

Enter a value in square kilometers and press the button to convert it to acres.

Square Kilometers (km²)

Result in Acres (ac)

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How to use

  1. Enter a value in “Square Kilometers (km²)”.
  2. Optionally set “Decimal Places” for formatted output.
  3. Select “Convert” to compute acres and view the calculation line.
  4. Use “Copy Result” to copy the numeric output.
  5. Use “Clear All” to reset inputs and outputs.
  6. “Swap” opens the inverse tool.

Definitions and unit facts

Square kilometer (km²) — SI derived unit of area equal to the area of a square 1000 m on a side. System: SI. Abbreviation: km². Exact relations: 1 km² = 1,000,000 m²; 1 km² = 247.105381467 ac. Imperial/US customary cross-reference: 1 km² ≈ 0.386102 mi².

Acre (ac) — Imperial/US customary unit of area defined exactly as 43,560 ft². Using the international foot (1 ft = 0.3048 m exactly), 1 ac = 4046.8564224 m² exactly. Exact relations used here: 1 ac = 0.0040468564224 km²; 1 km² = 247.105381467 ac. System: Imperial/US customary. Abbreviation: ac.

Square Kilometers to Acres Converter - km2 to ac

Conversion formula

ac = km² × (1,000,000 ÷ 4,046.8564224)

km² = ac × 0.0040468564224

Sources: NIST 

Conversion table

Square Kilometers (km²)Acres (ac)
0.0010.247105
0.0102.471054
0.05012.355269
0.10024.710538
0.20049.421076
0.500123.552691
1247.105381
2494.210763
2.5617.763454
51,235.526907
7.51,853.290360
102,471.053815
256,177.634537
5012,355.269073
7518,532.903610
10024,710.538147
25061,776.345367
500123,552.690734
750185,329.036100
1,000247,105.381467

Real-world examples

  • Central Park, NYC: 3.41 km² = 843 ac.
  • Golden Gate Park, San Francisco: 4.12 km² = 1,017 ac.
  • Griffith Park, Los Angeles: 17.44 km² = 4,310 ac.
  • Hyde Park, London: 1.42 km² = 350 ac.
  • Stanley Park, Vancouver: 4.05 km² = 1,001 ac.
  • Boston Common: 0.202 km² = 50 ac.
  • Disneyland Park (Anaheim): 0.344 km² = 85 ac.
  • Pentagon reservation: 2.36 km² = 583 ac.
  • Vatican City: 0.49 km² = 121 ac.
  • One U.S. public land survey section: 2.58999 km² = 640 ac.

What areas are you comparing with this tool? If another online calculator would help your work, please suggest it in the comments and we will consider building it.

CalcuLife.com