Acre to Square kilometer Converter
Type a value — the answer appears instantly. 1 ac = 0.00404686 km².
Reviewed by the OmniCalc teamMethod verified 2026-07-01
0.00404686 square kilometers
= 4,046.86 m²= 43,560 ft²
equals 0.00404686 square kilometersFormula: km² = ac × 0.0040468564
Acre to Square kilometer formula
km² = ac × 0.0040468564
Convert 5 acres to square kilometers
- Start with 5 acres.
- Multiply by the conversion factor: 5 × 0.00404686 = 0.0202343.
- So 5 ac = 0.0202343 km².
Acre to Square kilometer conversion table
| Acres (ac) | Square kilometers (km²) |
|---|---|
| 0.01 ac | 0.0000404686 km² |
| 0.1 ac | 0.000404686 km² |
| 0.25 ac | 0.00101171 km² |
| 0.5 ac | 0.00202343 km² |
| 1 ac | 0.00404686 km² |
| 2 ac | 0.00809371 km² |
| 3 ac | 0.0121406 km² |
| 4 ac | 0.0161874 km² |
| 5 ac | 0.0202343 km² |
| 6 ac | 0.0242811 km² |
| 7 ac | 0.028328 km² |
| 8 ac | 0.0323749 km² |
| 9 ac | 0.0364217 km² |
| 10 ac | 0.0404686 km² |
| 15 ac | 0.0607028 km² |
| 20 ac | 0.0809371 km² |
| 25 ac | 0.101171 km² |
| 30 ac | 0.121406 km² |
| 40 ac | 0.161874 km² |
| 50 ac | 0.202343 km² |
| 75 ac | 0.303514 km² |
| 100 ac | 0.404686 km² |
| 250 ac | 1.01171 km² |
| 500 ac | 2.02343 km² |
| 1,000 ac | 4.04686 km² |
| 5,000 ac | 20.2343 km² |
| 10,000 ac | 40.4686 km² |
Unit definitions
What is a acre?
The acre is exactly 4840 square yards, about 4046.86 square metres or 0.405 hectares. It is the traditional unit for land area in the United States and United Kingdom. An acre was historically the area a yoke of oxen could plough in a day.
What is a square kilometer?
The square kilometre is the area of a one-kilometre square, equal to one million square metres or 100 hectares. It is used for measuring cities, regions, and countries. One square kilometre is about 0.386 square miles.
Frequently asked questions
How many square kilometers are in one acre?
One acre equals 0.00404686 square kilometers (1 ac = 0.00404686 km²).
How do I convert acres to square kilometers?
Multiply the value in acres by 0.00404686. For example, 10 ac × 0.00404686 = 0.0404686 km².
Which is bigger — a acre or a square kilometer?
A square kilometer is bigger: one square kilometer contains 247.1054 acres.
Is this acre to square kilometer converter free?
Yes — the converter is free, works offline once loaded, and computes instantly in your browser without sending your numbers to a server.
Conversion factors follow international definitions (SI / NIST). Last verified 2026-07-01.