Kilometer/Second to Mile/Second Converter

Speed Converter

18 units available

Decimals:

From

To

0.621371

1 km/s = 0.621371 mi/s

Formula:

mi/s = km/s × 0.6213711922

With your value: 1 km/s = 0.62137119 mi/s

How big is that?

Everyday references on a logarithmic scale, all expressed in kilometer/second so you can sanity-check the result.

Urban speed limit (50 km/h) (1/72 your value)0.0139 km/s

Cheetah sprint (1/34 your value)0.0290 km/s

Motorway (110 km/h) (1/33 your value)0.0306 km/s

Airliner cruise (1/4.0 your value)0.250 km/s

Speed of sound (sea level) (1/2.9 your value)0.343 km/s

Your value1.00 km/s

Other Kilometer/Second to Mile/Second conversions

2 km/s to mi/s 3 km/s to mi/s 4 km/s to mi/s 5 km/s to mi/s 6 km/s to mi/s 7 km/s to mi/s 8 km/s to mi/s

Kilometer/Second to Mile/Second Conversion Table

Kilometer/Second (km/s)	Mile/Second (mi/s)
0.5	0.310686
1	0.621371
2	1.242742
5	3.106856
10	6.213712
15	9.320568
20	12.427424
25	15.53428
50	31.06856
100	62.137119
250	155.342798
500	310.685596
1000	621.371192

Mile/Second to Kilometer/Second Conversion Table

Mile/Second (mi/s)	Kilometer/Second (km/s)
0.5	0.804672
1	1.609344
2	3.218688
5	8.04672
10	16.09344
15	24.14016
20	32.18688
25	40.2336
50	80.4672
100	160.9344
250	402.336
500	804.672
1000	1,609.344

Where these values come from

Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.

Kilometer/Second (km/s)

Speed

Exact conversion

Derived quantity: a defined length divided by a defined time interval.

Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)

Bureau International des Poids et Mesures · Reviewed 2026-07-01

Mile/Second (mi/s)

Speed

Exact conversion

Derived quantity: a defined length divided by a defined time interval.

Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)

Bureau International des Poids et Mesures · Reviewed 2026-07-01

How to Convert Kilometer/Second to Mile/Second

To convert from Kilometer/Second (km/s) to Mile/Second (mi/s), multiply the value by 0.6213711922.

Formula: mi/s = km/s × 0.6213711922

Reverse: km/s = mi/s × 1.609344

Step-by-Step Example

Start with your value in Kilometer/Second. For example: 5 km/s
Multiply by the conversion factor: 5 x 0.6213711922
The result is: 3.106856 mi/s

About Kilometer/Second

The kilometer/second (km/s) is a unit of speed and velocity. One kilometer/second equals 1000 metre per seconds. UnitConvertLab converts it against every other speed unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: speed calculations, engineering and science, education.

About Mile/Second

The mile/second (mi/s) is a unit of speed and velocity. One mile/second equals 1609.344 metre per seconds. UnitConvertLab converts it against every other speed unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: speed calculations, engineering and science, education.

Frequently Asked Questions

How many Mile/Second are in 1 Kilometer/Second?

There are exactly 0.6213711922 Mile/Second in 1 Kilometer/Second. This means the conversion factor from Kilometer/Second to Mile/Second is 0.6213711922.

What is the formula to convert Kilometer/Second to Mile/Second?

The formula to convert Kilometer/Second to Mile/Second is: mi/s = km/s × 0.6213711922. For example, to convert 10 Kilometer/Second to Mile/Second, you would multiply 10 by 0.6213711922.

What is a Kilometer/Second?