Kilometer/Second to Millimeter/Second Converter

Speed Converter

18 units available

Decimals:

From

To

1,000,000

1 km/s = 1,000,000 mm/s

Formula:

mm/s = km/s × 1,000,000

With your value: 1 km/s = 1,000,000 mm/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 Millimeter/Second conversions

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

Kilometer/Second to Millimeter/Second Conversion Table

Kilometer/Second (km/s)	Millimeter/Second (mm/s)
0.5	500,000
1	1,000,000
2	2,000,000
5	5,000,000
10	10,000,000
15	15,000,000
20	20,000,000
25	25,000,000
50	50,000,000
100	100,000,000
250	250,000,000
500	500,000,000
1000	1,000,000,000

Millimeter/Second to Kilometer/Second Conversion Table

Millimeter/Second (mm/s)	Kilometer/Second (km/s)
0.5	5.000000e-7
1	1.000000e-6
2	2.000000e-6
5	5.000000e-6
10	1.000000e-5
15	1.500000e-5
20	2.000000e-5
25	2.500000e-5
50	5.000000e-5
100	0.0001
250	0.00025
500	0.0005
1000	0.001

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

Millimeter/Second (mm/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 Millimeter/Second

To convert from Kilometer/Second (km/s) to Millimeter/Second (mm/s), multiply the value by 1,000,000.

Formula: mm/s = km/s × 1,000,000

Reverse: km/s = mm/s × 0.000001

Step-by-Step Example

Start with your value in Kilometer/Second. For example: 5 km/s
Multiply by the conversion factor: 5 x 1,000,000
The result is: 5,000,000 mm/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 Millimeter/Second

The millimeter/second (mm/s) is a unit of speed and velocity. One millimeter/second equals 0.001 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 Millimeter/Second are in 1 Kilometer/Second?

There are exactly 1,000,000 Millimeter/Second in 1 Kilometer/Second. This means the conversion factor from Kilometer/Second to Millimeter/Second is 1,000,000.

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

The formula to convert Kilometer/Second to Millimeter/Second is: mm/s = km/s × 1,000,000. For example, to convert 10 Kilometer/Second to Millimeter/Second, you would multiply 10 by 1,000,000.

What is a Kilometer/Second?