Square Inches to Square Kilometers
An instant square inches-to-square kilometers converter, with the formula and a reference table below.
| Square Inches | Square Kilometers |
|---|---|
| 1 in² | 6.4516e-10 km² |
| 2 in² | 1.29032e-09 km² |
| 3 in² | 1.93548e-09 km² |
| 5 in² | 3.2258e-09 km² |
| 10 in² | 6.4516e-09 km² |
| 25 in² | 1.6129e-08 km² |
| 50 in² | 3.2258e-08 km² |
| 100 in² | 6.4516e-08 km² |
How to use
- Enter a value in the Square Inches field.
- The Square Kilometers figure appears immediately — no button to press.
- Typing in the Square Kilometers field converts back to Square Inches the same way.
- Use the reference table for the values that come up most often.
Square Inches to Square Kilometers formula
Converting square inches to square kilometers is a single multiplication by 6.4516e-10.
km² = in² × 6.4516e-10
Why this factor: the square inch and the square kilometer are both defined against the square meter, so dividing one definition by the other gives 6.4516e-10 directly. Both definitions are set out in full below.
To go the other way, divide by 6.4516e-10 — or use the Square Kilometers to Square Inches converter, which is the same calculation reversed.
Worked example
Given 1000 in², multiplying by 6.4516e-10 yields 6.4516e-07 km².
1000 in² × 6.4516e-10 = 6.4516e-07 km²
The converter above does this for any value you type, in either direction.
What is a square inch?
A square inch is the area of a one-inch square, used for small areas and pressure.
Definition: Exactly 0.00064516 square meter, following from the exact 25.4 mm inch.
Where it is used: Print and label areas, gasket and seal faces, and the denominator in psi.
What is a square kilometer?
A square kilometer is the area of a one-kilometer square — one million square meters.
Definition: Exactly 1×10⁶ square meters. Note it is the kilometer that is squared, not the prefix applied to a square meter.
Where it is used: City, national park and country areas, population density, and land cover statistics.
Square Inches vs Square Kilometers
The square inch is an imperial unit while the square kilometer is a metric unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many square kilometers are in a square inch?
One square inch equals 6.4516e-10 square kilometers.
What is the formula to convert square inches to square kilometers?
Multiply the number of square inches by 6.4516e-10. To reverse it, divide by 6.4516e-10 instead.
How do I convert square kilometers back to square inches?
Divide by 6.4516e-10, which is the same as multiplying by 1.5500031e+09.
How many square kilometers are in 10 square inches?
10 in² works out to 6.4516e-09 km².
How is the square inch defined?
Exactly 0.00064516 square meter, following from the exact 25.4 mm inch.