Square miles to Square kilometers Converter mi² → km²

1 square mile (mi²) = 2.58998811 square kilometers (km²). Type a value below — the conversion happens instantly, entirely on your device.

From

1 mi² = 2.58998811 km²

Precision

1 square miles = 2.5899881 square kilometers

1 × 2.58999 = 2.5899881

1 mi² equals 2.58999 km², so multiplying by 2.58999 converts the value. The result describes the exact same quantity — only the measuring stick changes.

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How to convert square miles to square kilometers

square kilometers = square miles × 2.58998811 — multiply the square mile value by 2.58999.

Example: 10 mi² = 25.8999 km².

To convert the other way: square miles = square kilometers ÷ 2.58998811 — or use the dedicated km² to mi² converter .

Square miles to Square kilometers conversion table

Square miles (mi²)	Square kilometers (km²)
0.1	0.25899881
0.25	0.64749703
0.5	1.2949941
1	2.5899881
2	5.1799762
3	7.7699643
4	10.359952
5	12.949941
6	15.539929
7	18.129917
8	20.719905
9	23.309893
10	25.899881
15	38.849822
20	51.799762
25	64.749703
30	77.699643
40	103.59952
50	129.49941
75	194.24911
100	258.99881
250	647.49703
500	1294.9941
1000	2589.9881

About the units

What is a square mile?

A square mile (mi²) is 640 acres, about 2.59 km². It is used for large land areas such as cities and counties in the US and UK.

What is a square kilometer?

A square kilometer (km²) is one million square meters (100 hectares). City and country areas are measured in square kilometers.

Frequently asked questions

How many square kilometers are in 1 square mile?

1 square mile (mi²) = 2.58998811 square kilometers (km²).

What is the formula to convert square miles to square kilometers?

square kilometers = square miles × 2.58998811 — multiply the square mile value by 2.58999.

How do I convert mi² to km² without a calculator?

Multiply by 2.59 for a close estimate. Exact factor: 1 mi² = 2.58998811 km².

Is this mi²-to-km² converter accurate and private?

Yes. It uses the exact internationally defined conversion factors and computes results locally in your browser — your input is never sent to a server, and the page keeps working offline.