I'm solving a physics kinematics problem that says a car is traveling at 100 km/h, but my equation needs the speed in m/s — what number do I use?

100 km/h = 27.78 m/s. The car travels about 27.78 m every second.

My lab partner recorded a speed in km/h but I need m/s for my SI-unit equation — what's the quickest way to convert it?

Divide by 3.6. Example: 36 km/h ÷ 3.6 = 10 m/s. This conversion is mathematically exact (3.6 = 3600 seconds / 1000 meters).

Why do physics textbooks use m/s in equations instead of km/h?

Meters per second is the SI unit for speed, derived from the base units meter and second. Using SI units throughout keeps formulas for kinematics, momentum, and energy consistent.

My cycling app shows my average speed as 28 km/h — how far do I travel each second?

28 km/h = 7.78 m/s, so you cover about 7.8 m every second. For the reverse conversion, see m/s to km/h.

Kilometers per Hour (km/h) to Meters per Second (m/s) Converter

Enter a value to instantly convert between speed units.

From

Precision4 dp

1 Kilometer per Hour = 0.2778 Meter per Second

Key Formulas

Kilometer per Hour → Mile per Hour

mph = km/h × 0.621371

Mile per Hour → Kilometer per Hour

km/h = mph × 1.60934

Knot → Mile per Hour

mph = kn × 1.15078

Mile per Hour → Knot

kn = mph × 0.868976

Formula

m/s = km/h ÷ 3.6

To convert kilometers per hour to meters per second, divide by 3.6. This is useful for physics problems, engineering calculations, and translating real-world speeds into SI units used in science.

Source: NIST SP 811, Table B.8

Reviewed by the Convert Calc editorial team · Last reviewed: 2026-10-06 · see our methodology

Frequently Asked Questions

Real-World Examples

Walking pace example. About 2.2 mph.

3.6 km/h = 1 m/s

Cycling speed example.

36 km/h = 10 m/s

About 45 mph.

72 km/h = 20 m/s

Aircraft speed example. 900 km/h is 250 m/s.

900 km/h = 250 m/s

kmh to mph mph to kmh knots to mph mph to knots ms to kmh

See This in Context

Travel Automotive