# Kilometers per hour to meters per second converter

> Convert kilometers per hour to meters per second (km/h to m/s) with the exact factor, a conversion chart and worked steps.

Interactive version: https://www.calcopenly.com/conversion/kmh-to-mps
Subject: Unit converters

A kilometer-per-hour reading combines a metric distance with an hour. Converting it is useful for a vehicle comparison or a physics problem expressed in seconds. Keep instantaneous speed separate from a whole-trip average that includes stops.

One kilometre per hour is about 0.2777777778 meters per second, so 100 km/h is 27.777778 m/s. To convert km/h to m/s, multiply by 0.2777777778; to convert back, multiply by 3.6.

One kilometre per hour is 1,000 m in 3,600 s, so 1 m/s is exactly 3.6 km/h. The factor has no exact decimal form, so results are computed with 50 significant digits and rounded only for display.

## Inputs

- **Kilometers per hour (km/h)**

## Results

- Meters per second (m/s) — main result
- Conversion
- 1 m/s in kilometers per hour (km/h)

## Formula

$$
\text{meters per second} = \text{kilometers per hour} \times 0.277777777778
$$

## Worked examples

### 100 km/h to m/s

- Kilometers per hour (km/h): 100 km/h
- **Meters per second: 27.7777777778 m/s**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 30 km/h to m/s

- Kilometers per hour (km/h): 30 km/h
- **Meters per second: 8.3333333333 m/s**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 120 km/h to m/s

- Kilometers per hour (km/h): 120 km/h
- **Meters per second: 33.3333333333 m/s**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

## Questions

### When would I convert km/h to m/s?

A kilometer-per-hour reading combines a metric distance with an hour. Converting it is useful for a vehicle comparison or a physics problem expressed in seconds. Keep instantaneous speed separate from a whole-trip average that includes stops.

### How many meters per second are in a kilometre per hour?

One kilometre per hour is about 0.2777777778 meters per second. One kilometre per hour is 1,000 m in 3,600 s, so 1 m/s is exactly 3.6 km/h.

### How do you convert km/h to m/s?

Multiply the number of kilometers per hour by 0.2777777778. For example, 100 km/h × 0.2777777778 = 27.777778 m/s. To go the other way, divide by 0.2777777778.

### How can I estimate km/h to m/s without a calculator?

Multiply by 0.28. That is 0.8% high of the exact factor 0.2777777778, so 100 km/h comes out as 28 m/s instead of 27.7778.

### How accurate is the kilometers per hour to meters per second converter?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 3 worked examples whose answers come from independent sources; for example, “100 km/h to m/s” is checked against Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions).

### Where does the method come from?

NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B; NIST Handbook 44, Appendix C: General tables of units of measurement; BIPM, The International System of Units (SI Brochure), 9th edition.

## Sources

- [NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C: General tables of units of measurement](https://www.nist.gov/pml/weights-and-measures/publications/nist-handbooks/handbook-44)
- [BIPM, The International System of Units (SI Brochure), 9th edition](https://www.bipm.org/en/publications/si-brochure)