Acres to square kilometres converter

Convert acres (ac) to square kilometres (km²).

Area converter

Instant conversion

Edit either value. Decimals and scientific notation supported.

From value

From unit

To value

km²

To unit

CONVERSION

1 ac ≈ 0.004046856422 km²

Display precision

Precision changes displayed rounding, not calculation accuracy.

FORMULAkm² = ac × 0.0040468564224

FORMULA & EXAMPLES

How to convert Acres to square kilometres

km² = ac × 0.0040468564224

Multiply the ac reading by 0.0040468564224.

Worked examples

1 ac ≈ 0.004046856422 km²

1 × 0.0040468564224 ≈ 0.004046856422

640 ac ≈ 2.58998811 km²

640 × 0.0040468564224 ≈ 2.58998811

Frequently asked questions

Why is ac to km² different from a length conversion?

Area factors scale with the square of the length factor. For example, 1 ft = 0.3048 m gives 1 ft² = 0.3048² m² = 0.09290304 m².

Acres to square kilometres table

Fixed reference · Acre to Square kilometre

Reference values use this page’s named pair and default context. Calculator precision and font settings do not change this table.

Acre (ac)	Square kilometre (km²)
0	0
0.1	0.0004046856422
0.5	0.002023428211
1	0.004046856422
2	0.008093712845
5	0.02023428211
10	0.04046856422
25	0.1011714106
50	0.2023428211
100	0.4046856422
1000	4.046856422

Table results use 10 significant figures; decimal formula coefficients use up to 15. Calculations use the unit definitions before rounding. Extra digits do not improve measurement accuracy.