Acre to Square Kilometer Converter

Area Converter

20 units available

Decimals:

From

To

0.004047

1 ac = 0.004047 km²

Formula:

km² = ac × 0.0040468564

With your value: 1 ac = 0.00404686 km²

How big is that?

Everyday references on a logarithmic scale, all expressed in acre so you can sanity-check the result.

Parking space (1/3.2e+2 your value)0.00309 ac

Tennis court (1/16 your value)0.0645 ac

Your value1.00 ac

Football pitch (1.8× your value)1.76 ac

Hectare (2.5× your value)2.47 ac

Central Park (8.4e+2× your value)843 ac

Other Acre to Square Kilometer conversions

2 ac to km² 3 ac to km² 4 ac to km² 5 ac to km² 6 ac to km² 7 ac to km² 8 ac to km²

Acre to Square Kilometer Conversion Table

Acre (ac)	Square Kilometer (km²)
0.5	0.002023
1	0.004047
2	0.008094
5	0.020234
10	0.040469
15	0.060703
20	0.080937
25	0.101171
50	0.202343
100	0.404686
250	1.011714
500	2.023428
1000	4.046856

Square Kilometer to Acre Conversion Table

Square Kilometer (km²)	Acre (ac)
0.5	123.552691
1	247.105381
2	494.210763
5	1,235.526907
10	2,471.053815
15	3,706.580722
20	4,942.107629
25	6,177.634537
50	12,355.269073
100	24,710.538147
250	61,776.345367
500	123,552.690734
1000	247,105.381467

Where these values come from

Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.

Acre (ac)

Area

Exact conversion

Derived from the square metre via the length definitions above.

Source: NIST Special Publication 811, Guide for the Use of the International System of Units

National Institute of Standards and Technology (US) · Reviewed 2026-07-01

Square Kilometer (km²)

Area

Exact conversion

Derived from the square metre via the length definitions above.

Source: NIST Special Publication 811, Guide for the Use of the International System of Units

National Institute of Standards and Technology (US) · Reviewed 2026-07-01

How to Convert Acre to Square Kilometer

To convert from Acre (ac) to Square Kilometer (km²), multiply the value by 0.0040468564.

Formula: km² = ac × 0.0040468564

Reverse: ac = km² × 247.1053814672

Step-by-Step Example

Start with your value in Acre. For example: 5 ac
Multiply by the conversion factor: 5 x 0.0040468564
The result is: 0.020234 km²

About Acre

The acre is a unit of land area equal to 43,560 square feet or about 4,047 square meters. It is used primarily in the US, UK, and former British colonies.

Fun Fact: An acre was originally defined as the amount of land a yoke of oxen could plow in one day.

Common uses: land measurement, agriculture, real estate.

About Square Kilometer

The square kilometer (km²) is a unit of area. One square kilometer equals 1.000000 × 10^+6 square metres. UnitConvertLab converts it against every other area unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: area calculations, engineering and science, education.

Frequently Asked Questions

How many Square Kilometer are in 1 Acre?

There are exactly 0.0040468564 Square Kilometer in 1 Acre. This means the conversion factor from Acre to Square Kilometer is 0.0040468564.

What is the formula to convert Acre to Square Kilometer?

The formula to convert Acre to Square Kilometer is: km² = ac × 0.0040468564. For example, to convert 10 Acre to Square Kilometer, you would multiply 10 by 0.0040468564.

What is a Acre?