Speed Converter - Convert Speed Units
Convert millimeters, centimeters, and meters per second, kilometers per hour, inches, feet, and yards per second, miles per hour, and knots.
What Is a Speed Converter?
A speed converter converts a speed magnitude from one unit to another. This tool supports metric units (mm/s, cm/s, m/s, km/h), US customary units (in/s, ft/s, yd/s, mph), and the knot used in aviation and maritime navigation.
How to Use This Converter
- Enter a non-negative speed value — Changing the value does not update the displayed result yet.
- Select From — Choose the unit of the value you entered. The displayed result stays unchanged until you convert.
- Select To — Choose the unit you want to convert to. The displayed result still waits for Convert.
- Click Convert or press Enter — Calculate the result.
- Swap — Reverse the From and To units and convert using the current value.
- Copy Result — Copy the currently displayed conversion result.
- Reset — Restore the default 1 meter per second to kilometers per hour conversion.
Speed Unit Conversion Table
All factors below are the same values used by the converter. A knot is exactly one international nautical mile per hour (1 nautical mile = 1,852 meters).
| Group | Unit | Abbreviation | Conversion to m/s |
|---|---|---|---|
| Metric / SI | Millimeter per second | mm/s | 0.001 m/s |
| Metric / SI | Centimeter per second | cm/s | 0.01 m/s |
| Metric / SI | Meter per second | m/s | 1 m/s |
| Metric / SI | Kilometer per hour | km/h | 0.2777777777777778 m/s |
| US customary | Inch per second | in/s | 0.0254 m/s |
| US customary | Foot per second | ft/s | 0.3048 m/s |
| US customary | Yard per second | yd/s | 0.9144 m/s |
| US customary | Mile per hour | mph | 0.44704 m/s |
| Nautical / aviation | Knot | kn | 0.5144444444444445 m/s |
Metric, Everyday, and Nautical Speeds
Meters per second are common in science and engineering. Kilometers per hour and miles per hour are the usual road-speed units. Knots are used for aircraft and ships. Small metric units (mm/s, cm/s) and inch/foot/yard per second are useful for machinery and lab work.
Practical Uses
- Travel: Convert posted speed limits between km/h and mph.
- Vehicles: Compare speedometer units.
- Aviation and maritime: Convert knots to km/h or mph.
- Science and engineering: Convert m/s, cm/s, and mm/s.
- Weather: Convert reported wind speeds.
Common Speed Conversions
| From | To | Conversion |
|---|---|---|
| 1 m/s | km/h | 3.6 km/h |
| 1 km/h | m/s | 0.277777777778 m/s |
| 1 mph | km/h | 1.609344 km/h |
| 1 knot | km/h | 1.852 km/h |
| 1 ft/s | m/s | 0.3048 m/s |
| 1 yd/s | m/s | 0.9144 m/s |
| 1 in/s | m/s | 0.0254 m/s |
| 1 m/s | cm/s | 100 cm/s |
| 1 m/s | mm/s | 1,000 mm/s |
Frequently Asked Questions
What units does the Speed Converter support?
It supports millimeters, centimeters, and meters per second; kilometers per hour; inches, feet, and yards per second; miles per hour; and knots.
How many kilometers per hour is 1 meter per second?
Exactly 3.6 km/h. That follows from 1 m/s × 3,600 s/h ÷ 1,000 m/km.
How many kilometers per hour is 1 mile per hour?
Exactly 1.609344 km/h, using the international mile of 1,609.344 meters.
How many kilometers per hour is 1 knot?
Exactly 1.852 km/h, because 1 knot is 1 international nautical mile per hour and 1 nautical mile is 1,852 meters.
What is a knot?
A knot (kn) is a speed of one nautical mile per hour. It is used in aviation and maritime navigation.
Is a knot exactly 1.852 km/h?
Yes, under the international nautical mile of 1,852 meters. This converter uses that definition (0.5144444444444445 m/s).
How many meters per second are in 1 km/h?
Mathematically 0.2777777777777778 m/s (1,000 ÷ 3,600). The result display may show about 0.277777777778 to keep meaningful precision.
Can this converter convert negative speeds?
No. It converts speed magnitude, so negative values are rejected.
Does the converter update automatically?
No. Changing Value, From, or To does not update the result. Click Convert or press Enter in the Value field.
How accurate are the conversions?
Conversions use exact defined factors (international foot, mile, and nautical mile) as represented in JavaScript. Results are formatted to keep meaningful precision without padding extra zeros.
Is this speed converter free?
Yes. It is free to use, with no registration or subscription. After the page loads, the converter also works offline.