Skip to content
UnitCalculators.com

Square kilometres to square miles

Multiply square kilometres by 0.386102 to get square miles.

1 km² = 0.386102 mi²BIPM SI · NIST HB 44
km²
9.6526mi²

25 km² = 9.6526 mi²

How to convert square kilometres to square miles

The square mile is exactly 2 589 988.110336 m² (1609.344 m squared). The square kilometre is one million square metres (10⁶ m²).

Worked example — 25 km²: 25 × 0.386102 = 9.6526 mi².

Square kilometres to square miles table

Common conversions. The reverse table is on square miles to square kilometres.
Square kilometresSquare miles
1 km²0.386102 mi²
2 km²0.772204 mi²
5 km²1.9305 mi²
10 km²3.861 mi²
25 km²9.6526 mi²
50 km²19.3051 mi²
100 km²38.6102 mi²
500 km²193.0511 mi²
1,000 km²386.1022 mi²

Reverse and related

About square kilometres and square miles

Square kilometre (km²)

1 km² = 0.386102 mi²

Definition. One million square metres (10⁶ m²)

History and origin

The square kilometre is a square one kilometre on each side, one million square metres. It became the metric unit for large land areas.

Current use

Square kilometres measure land area and the size of cities and regions.

Source: BIPM SI Brochure (2019)

Square mile (mi²)

1 mi² = 2.59 km²

Definition. Exactly 2 589 988.110336 m² (1609.344 m squared)

History and origin

The square mile is a square one mile on each side, built from the statute mile. It equals about 2.59 square kilometres, or 640 acres.

Current use

Square miles measure land, counties and regions in the United States and United Kingdom.

Source: NIST Handbook 44, Appendix C (area); 1959 yard-and-pound agreement

Where people use this

Square kilometres: land area, city and region sizes. Square miles: land and county area. 1 km² is about 0.386 sq mi.

How we know this is right
The factor is fixed by the standards that define the units, not chosen — so it is exact, not a measurement:
1 mi² = 2.58998811 km², so 1 km² = 1 ÷ 2.58998811 = 0.386102 mi².

Every value is carried to full double precision; the display is rounded.

Sources: NIST Handbook 44, Appendix C (area); 1959 yard-and-pound agreement; BIPM SI Brochure (2019).

Questions people ask

How many sq mi in a km²?

One square kilometre is about 0.386 square miles.

How many sq mi is 10 km²?

10 km² is about 3.86 sq mi.

How many km² is a square mile?

One square mile is about 2.59 km².

All square kilometre conversions