Speed converter
Convert kilometres per hour, miles per hour, metres per second, knots and feet per second.
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How it works
Convert scalar speed between road, nautical and SI units. Factors account for both the distance unit and the time unit, using international miles and the exact 1852-meter nautical mile.
A few things to know
Speed magnitude only; negative values are rejected. Does not convert pace, acceleration, directional velocity, travel duration or Mach number. Mach requires local conditions and is intentionally excluded. No travel or weather forecast is made. Display uses up to 12 significant digits; this is not arbitrary-precision arithmetic or a measurement calibration. Numeric magnitude is bounded to 1e100, with nonzero inputs at least 1e-100.
When to use this tool
Speed combines a distance unit with a time unit, so both parts matter when moving between meters per second, kilometers per hour, miles per hour and knots. This converter handles a nonnegative speed magnitude using international mile and foot definitions and the exact nautical mile. It shows the selected equivalent and a table of all supported speeds. It does not turn a speed into a journey estimate, running pace or directional velocity; those require additional information or a different relationship.
- Compare road-speed specifications using mph and km/h.
- Translate a nautical speed in knots into a kilometer-per-hour value.
- Express a measured speed in meters per second for a separate calculation that requires SI units.
How to use speed converter
Enter the speed magnitude
Use Value for a nonnegative numeric speed. Enter the number without mph, km/h or other unit suffixes.
Choose the starting speed unit
Set From unit to match the source. A knot is a nautical mile per hour, while mph uses international miles per hour.
Read the new expression
Choose To unit and calculate. Check Converted value or download the equivalent-speed table if several unit systems are needed.
Sixty miles per hour in metric units
Inputs
Value 60; From unit International miles per hour (mph); To unit Kilometers per hour (km/h).
Result
Converted value is 96.56064 kilometers per hour. The equivalent speed in the table is 26.8224 meters per second.
What it means
The international mile is 1.609344 kilometers, so multiplying 60 mph by that factor gives 96.56064 km/h. The hour remains the same in that conversion; changing to seconds requires the additional time factor.
Common mistakes to avoid
Mixing speed and pace
Minutes per kilometer is a reciprocal quantity, not another label for kilometers per hour. This converter does not accept pace inputs.
Treating knots as mph
Knots use nautical miles, which are longer than international miles. The source unit must be selected explicitly.
Inferring a trip duration
Travel time also requires distance and an appropriate average speed. A converted instantaneous reading is not a journey forecast.
Frequently asked questions
Definitions, edge cases, and practical next steps for this tool. Search all tool FAQs ↗
How is a speed converted?
The source unit is expressed in meters per second, multiplied by the input value, then divided by the destination’s meters-per-second factor. This accounts for distance and time together rather than applying only a length conversion.
How many km/h are in one m/s?
One meter per second equals 3.6 kilometers per hour. Over 3,600 seconds, one meter each second gives 3,600 meters, or 3.6 kilometers. The same factor can be reversed by dividing km/h by 3.6.
What is a knot?
A knot is one nautical mile per hour. The converter uses a nautical mile of 1,852 meters, so one knot equals 1.852 km/h. It is a speed unit, while a nautical mile by itself is a distance unit.
Can I convert running pace here?
The supported inputs are distance per time, not time per distance. A pace such as five minutes per kilometer needs a reciprocal calculation before it becomes a speed. Do not enter the pace number into a speed field and expect the same meaning.
Why is Mach number absent?
Mach relates speed to the local speed of sound, which depends on conditions. A fixed unit multiplier cannot universally convert it. The converter therefore excludes Mach instead of choosing an unstated temperature or atmospheric assumption.
Can speed be negative?
This tool treats speed as a magnitude, so negative values are rejected and zero is accepted. A signed component of velocity can represent direction, but the converter does not know an axis or vector reference and does not interpret directional motion.
Can I use the result to calculate travel time?
You can use the converted speed as one input to a separate distance-divided-by-speed calculation, provided speed is an appropriate average. Stops, changing speed, routes and conditions are not modeled here. Keep the distance and time units consistent in that next calculation.
Why should I avoid rounding early?
Rounding the source before converting can add an unnecessary difference, especially if the converted value is reused. Enter the original available reading and round the final result for your purpose. The converter displays up to 12 significant digits but cannot improve the original measurement.
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Sources and method
Use the references below to check definitions and platform guidance. The model’s scope and limits are explained above. Read our editorial standards.