Speed of Light to Kilometer/Second Converter

Speed Converter

18 units available

Decimals:

From

To

299,792.458

1 c = 299,792.458 km/s

Formula:

km/s = c × 299,792.458

With your value: 1 c = 299,792.458 km/s

How big is that?

Everyday references on a logarithmic scale, all expressed in speed of light so you can sanity-check the result.

Urban speed limit (50 km/h) (1/2.2e+7 your value)4.64e-8 c

Cheetah sprint (1/1.0e+7 your value)9.67e-8 c

Motorway (110 km/h) (1/9.8e+6 your value)1.02e-7 c

Airliner cruise (1/1.2e+6 your value)8.34e-7 c

Speed of sound (sea level) (1/8.7e+5 your value)0.00000114 c

Your value1.00 c

Other Speed of Light to Kilometer/Second conversions

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

Speed of Light to Kilometer/Second Conversion Table

Speed of Light (c)	Kilometer/Second (km/s)
0.5	149,896.229
1	299,792.458
2	599,584.916
5	1,498,962.29
10	2,997,924.58
15	4,496,886.87
20	5,995,849.16
25	7,494,811.45
50	14,989,622.9
100	29,979,245.8
250	74,948,114.5
500	149,896,229
1000	299,792,458

Kilometer/Second to Speed of Light Conversion Table

Kilometer/Second (km/s)	Speed of Light (c)
0.5	1.667820e-6
1	3.335641e-6
2	6.671282e-6
5	1.667820e-5
10	3.335641e-5
15	5.003461e-5
20	6.671282e-5
25	8.339102e-5
50	0.000167
100	0.000334
250	0.000834
500	0.001668
1000	0.003336

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.

Speed of Light (c)

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

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

How to Convert Speed of Light to Kilometer/Second

To convert from Speed of Light (c) to Kilometer/Second (km/s), multiply the value by 299,792.458.

Formula: km/s = c × 299,792.458

Reverse: c = km/s × 0.0000033356

Step-by-Step Example

Start with your value in Speed of Light. For example: 5 c
Multiply by the conversion factor: 5 x 299,792.458
The result is: 1,498,962.29 km/s

About Speed of Light

The speed of light (c) is a unit of speed and velocity. One speed of light equals 2.997925 × 10^+8 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 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.

Frequently Asked Questions

How many Kilometer/Second are in 1 Speed of Light?

There are exactly 299,792.458 Kilometer/Second in 1 Speed of Light. This means the conversion factor from Speed of Light to Kilometer/Second is 299,792.458.

What is the formula to convert Speed of Light to Kilometer/Second?

The formula to convert Speed of Light to Kilometer/Second is: km/s = c × 299,792.458. For example, to convert 10 Speed of Light to Kilometer/Second, you would multiply 10 by 299,792.458.

What is a Speed of Light?