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Speed converter

kilometer per second to mile per second

Convert kilometer per second (km/s) to mile per second (mi/s). Use an editable speed converter, conversion formula, and reference table.

0.6213711922

1 km/s = 0.6213711922 mi/s

Calculated in your browser

Conversion formula

mi/s = km/s × 0.6213711922

One kilometer per second equals 0.6213711922 mile per second. Multiply your value in kilometer per second by this factor to get mile per second. For the reverse conversion, divide by the same factor.

Worked example

To convert 5 kilometer per second:
5 × 0.6213711922 = 3.106855961 mi/s

Conversion table

kilometer per second (km/s)mile per second (mi/s)
0.010.006213711922
0.10.06213711922
10.6213711922
21.242742384
53.106855961
106.213711922
2515.53427981
5031.06855961
10062.13711922
1000621.3711922

About these measurements

Speed is distance traveled per unit of time.

The base reference used here is the meter per second. One kilometer per second is 1,000 base units; one mile per second is 1,609.344 base units.

Important distinctions

Mach is excluded because the speed of sound depends on medium and temperature.

Precision

The converter uses stored conversion factors and floating-point arithmetic. Results display up to ten significant digits, switching to scientific notation for very small or large values. Keep the precision of your original measurement when reporting results.

Common questions

How do I convert km/s to mi/s?

Multiply the quantity in km/s by 0.6213711922. You can also type the value into the converter above.

Can I reverse the conversion?

Yes. Use the swap button or open the mile per second to kilometer per second converter.

Reference

NIST Guide to the SI — conversion factors and prefix conventions. SI prefixes scale units by powers of ten; the dimension-specific notes above describe the assumptions used on this page.

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