Conversion method
A knot is one nautical mile (1,852 meters) per hour. Mach is included as a sea-level approximation at 340.29 m/s; actual sound speed changes with atmospheric conditions.
mph = x × 0.621371192237334
10 km/h = 6.213712 mph.
| km/h | mph |
|---|---|
| 1 | 0.621371 |
| 5 | 3.106856 |
| 10 | 6.213712 |
| 25 | 15.53428 |
| 50 | 31.06856 |
| 100 | 62.137119 |
Unit definitions and sources
Mach here assumes dry air near 15 °C, approximately 340.29 m/s. Actual sound speed varies with temperature and medium.
18 of the 24 definitions below were checked against the cited sources on 2026-09-20 (AI-assisted check).
| Unit and system | Use | Definition | Relationship |
|---|---|---|---|
| Meter per second (m/s); si | Common units | Meter per second measures speed. mps = (value in m/s) × 1. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Kilometer per hour (km/h); si | Common units | Kilometer per hour measures speed. mps = (value in km/h) × 0.2777777777777778. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Mile per hour (mph); us | Common units | Mile per hour measures speed. mps = (value in mph) × 0.44704. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Knot (kn); other | Common units | Knot measures speed. mps = (value in kn) × 0.5144444444444445. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Foot per second (ft/s); us | Specialist units | Foot per second measures speed. mps = (value in ft/s) × 0.3048. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Mach (sea level) (Ma); other | Specialist units | Mach (sea level) measures speed. mps = (value in Ma) × 340.29. Common use: Travel speed. | Approximate / conventional |
| Kilometer per second (km/s); si | Specialist units | A kilometer per second is exactly 1,000 meters per second. Common use: High-speed scientific measurements. | Exact definition; numerical display may be rounded |
| Centimeter per second (cm/s); other | Specialist units | Centimeter per second: multiply by 0.01 to obtain the category base unit. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Inch per second (in/s); other | Specialist units | Inch per second: multiply by 0.0254 to obtain the category base unit. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Meter per minute (m/min); other | Specialist units | Meter per minute: multiply by 0.016666666666666666 to obtain the category base unit. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Foot per minute (ft/min); other | Specialist units | Foot per minute: multiply by 0.00508 to obtain the category base unit. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Mile per second (mi/s); other | Specialist units | Mile per second: multiply by 1609.344 to obtain the category base unit. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Meter/hour (m/(h)); other | Specialist units | meter/hour = 0.0002777777777777778 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Kilometer/minute (km/(min)); other | Specialist units | kilometer/minute = 16.666666666666668 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Centimeter/hour (cm/(h)); other | Specialist units | centimeter/hour = 2.777777777777778e-06 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Centimeter/minute (cm/(min)); other | Specialist units | centimeter/minute = 0.00016666666666666666 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Millimeter/hour (mm/(h)); other | Specialist units | millimeter/hour = 2.7777777777777776e-07 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Millimeter/minute (mm/(min)); other | Specialist units | millimeter/minute = 1.6666666666666667e-05 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Millimeter/second (mm/(s)); other | Specialist units | millimeter/second = 0.001 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Foot/hour (ft/(h)); other | Specialist units | foot/hour = 8.466666666666667e-05 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Yard/hour (yd/(h)); other | Specialist units | yard/hour = 0.000254 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Yard/minute (yd/(min)); other | Specialist units | yard/minute = 0.01524 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Yard/second (yd/(s)); other | Specialist units | yard/second = 0.9144 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
| Mile/minute (mi/(min)); other | Specialist units | mile/minute = 26.8224 mps, derived from the component SI/customary definitions. Common use: Travel speed. | Exact definition; numerical display may be rounded |
Sources: BIPM: International System of Units; NIST: SP 811 Appendix B.8: conversion factors; NASA: Speed of sound; BIPM: SI prefixes
Precision of speed conversions
All 24 speed units convert through Meter per second (m/s). 23 have an exact defined relationship to the base unit and 1 is conventional or measured values. Results and the tables on this page come from the same engine, so a table value can be checked against the converter directly.
Standard display shows up to six decimal places, switching to scientific notation for very large or small values. Calculation uses JavaScript binary floating point independently of display rounding, so extra digits are not a claim about measurement accuracy. Each unit lists its own source; a citation records where the definition comes from, not an independent review. See Conversion methodology for the review and correction process.