Square miles to Square kilometers Converter
Convert Square miles (mi²) to Square kilometers (km²) instantly, or use the conversion table below to look up common values.
Square miles to Square kilometers conversion table
| Square miles (mi²) | Square kilometers (km²) |
|---|---|
| 1 | 2.589988 |
| 2 | 5.179976 |
| 3 | 7.769964 |
| 4 | 10.359952 |
| 5 | 12.949941 |
| 10 | 25.899881 |
| 25 | 64.749703 |
| 50 | 129.499406 |
| 100 | 258.998811 |
How to convert Square miles to Square kilometers
1 mi² equals 2.589988 km². Use the converter above for any value, or read the table for common conversions.
km² = mi² × 2.5899881103360003 · mi² = km² × 0.38610215854244584Multiply a square miles figure by 2.589988 to get square kilometers, or divide it by 0.386102 to go the other way.
Worked examples
- 1 mi²= 2.589988 km²
- 5 mi²= 12.949941 km²
- 10 mi²= 25.899881 km²
- 25 mi²= 64.749703 km²
- 100 mi²= 258.998811 km²
What these units are
Square miles (mi²). A square mile is about 2.59 square kilometers, or exactly 640 acres. It is used for land and territory areas in the United States and the UK, and for large ranch or park sizes.
Square kilometers (km²). A square kilometer is one million square meters. It is used for districts, national parks and country areas — and one square kilometer is exactly 100 hectares.
Every factor is an exact definition, so the only loss is display rounding. Land figures quoted in acres and hectares are usually rounded at the source.
Converting Square miles to Square kilometers in practice
Working in square miles
A square mile is the area of a square one mile on each side, exactly 2.589988110336 square kilometers, or exactly 640 acres. It is built from the statute mile and never from the nautical mile.
Metropolitan areas, counties, states, large ranches and national parks are measured in square miles in those countries. Weather maps and watershed studies also report extents in square miles.
The relation to acres is exact, with 640 acres in one square mile, and the relation to square kilometers follows from the exact definition of the mile. Rounded display can perturb the last digit of a two-way conversion.
Treating square miles as if they were mile figures is the usual slip: an area scales with the square of the length, so a square mile is not 1.609 square kilometers. Land is often better compared in acres or hectares.
Square miles, acres and square kilometers all describe large areas, and the relations are exact: 640 acres to a square mile, 2.59 square kilometers to the same measure. A county in one unit and a park in another do not compare until both are converted.
Reading the result in square kilometers
A square kilometer is the area of a square one kilometer on each side, exactly 1,000,000 square meters or 100 hectares. It is the usual metric unit for large areas.
City and district areas, national parks, reservoirs, islands and administrative regions are measured in square kilometers. Satellite imagery and land-cover studies report extents this way as well.
One square kilometer equals exactly 0.386102158542 square miles, from the exact mile definition. Since output is rounded, a large area converted into square miles and back can return with the last digit changed.
The mistake is forgetting that a square kilometer is a million square meters, so a figure in hectares must be divided by one hundred, not multiplied. Square kilometers also describe area, never distance.
Square kilometers are the usual large-area unit; hectares divide each one into a hundred parts and square miles are 2.59 square kilometers each. Using hectares for a district, or square kilometers for a plot, misplaces the scale by a factor of a hundred either way.
Checking a square miles to square kilometers conversion
Area factors are the square of the corresponding length factors, so the numbers move much faster than a reader expects. A square meter contains 10,000 square centimeters, and a square kilometer a million square meters, not a thousand.
The units that share a name across systems are still different sizes: a square mile and a square kilometer differ by a factor of about 2.59, and an acre is a fixed area rather than a square with equal sides, so it does not convert like the length units it is named after.
Land is where the reciprocal matters most, because acres and hectares are both in use for the same plots. When a figure moves between them, check it against a shape you can picture — a hectare is a square 100 meters on each side — rather than against the number alone.
Tanzania reference points
Real quantities, converted into the units on this page.
The total surface area of Tanzania, including Zanzibar
947,303 km² = 365,755.733094 mi²
Source: UN Statistics Division — World Statistics Pocketbook, country profile: Tanzania · verified 2026-09-14
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