Square kilometres to Square miles
1 square kilometre = 0.3861 square miles · 1 mi² = 2.59 km²
1 square kilometre = 0.3861 square miles
How it’s calculated
mi² = km² × 0.3861021585
- Multiply the value in square kilometres by 0.3861021585.
- To go back, divide by 0.3861021585 (or multiply by 2.58998811).
- 1 km² = 0.3861021585 mi² · 1 mi² = 2.58998811 km²
Show worked solutionFactor, unit cancellation and rounding, step by step
Find the conversion factor
By definition 1 km² = 1000000 m² and 1 mi² = 2589988.110336 m², so 1 mi² = 2.589988110336 km². Source: BIPM SI Brochure (9th ed.) (SI prefixes and accepted units); NIST SP 811 / Handbook 44.
Multiply by the factor written as a fraction
Put km² in the denominator so it cancels, leaving mi².
Calculate (unrounded)
Round the answer
Rounded to 5 significant figures.
Answer: 0.3861 mi²
1 km² in other units
Batch convert km² → mi²
- 1 km² = 0.3861 mi²
- 5 km² = 1.9305 mi²
- 10 km² = 3.861 mi²
- 25 km² = 9.6526 mi²
Quick examples
- 1 square kilometre = 0.3861 square miles
- 5 square kilometres = 1.9305 square miles
- 10 square kilometres = 3.861 square miles
- 25 square kilometres = 9.6526 square miles
- 100 square kilometres = 38.61 square miles
About these units
Square kilometre (km²)
SI (metric)
1 km² = 1000000 m²
Source: BIPM SI Brochure (9th ed.) (SI prefixes and accepted units)
Square mile (mi²)
US & imperial (identical)
1 mi² = 2589988.11 m²
Source: NIST SP 811 / Handbook 44
Square kilometres to square miles conversion table
| Square kilometres (km²) | Square miles (mi²) |
|---|---|
| 0.1 km² | 0.03861 mi² |
| 0.5 km² | 0.19305 mi² |
| 1 km² | 0.3861 mi² |
| 2 km² | 0.7722 mi² |
| 3 km² | 1.1583 mi² |
| 4 km² | 1.5444 mi² |
| 5 km² | 1.9305 mi² |
| 6 km² | 2.3166 mi² |
| 7 km² | 2.7027 mi² |
| 8 km² | 3.0888 mi² |
| 9 km² | 3.4749 mi² |
| 10 km² | 3.861 mi² |
| 15 km² | 5.7915 mi² |
| 20 km² | 7.722 mi² |
| 25 km² | 9.6526 mi² |
| 30 km² | 11.583 mi² |
| 40 km² | 15.444 mi² |
| 50 km² | 19.305 mi² |
| 75 km² | 28.958 mi² |
| 100 km² | 38.61 mi² |
| 250 km² | 96.526 mi² |
| 500 km² | 193.05 mi² |
| 1,000 km² | 386.1 mi² |
Related conversions
Frequently asked questions
How do I convert square kilometres to square miles?
Use mi² = km² × 0.3861021585. Multiply the value in square kilometres by 0.3861021585.
How many square miles are in 1 square kilometre?
1 square kilometre (km²) equals 0.3861 square miles (mi²); more precisely 0.3861021585.
How many square kilometres are in 1 square mile?
1 square mile (mi²) equals 2.59 square kilometres (km²); more precisely 2.58998811.
What is 10 km² in mi²?
10 square kilometres = 3.861 square miles.
Formula: mi² = km² × 0.3861021585. Factors last reviewed 2026-10-27.