Speed Converter
Free online Speed Converter to convert between mph, km/h, m/s, and knots instantly.
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The Speed Converter instantly converts between miles per hour, kilometers per hour, meters per second, and knots. Whether you're reading a foreign speed limit, logging a run, plotting a sailing course, or solving a physics problem, it delivers the exact speed in one click.
Four Units, Four Worlds
Speed is measured differently depending on what's moving. Cars use mph or km/h, runners often track in both, sailors and pilots use knots, and physics works in meters per second. Each unit fits its domain, but the moment you cross between them — a US speed limit for a metric driver, a nautical chart for a landlubber — you need a conversion.
How to Convert
- Enter the speed value.
- Choose the from and to units.
- Read the converted result instantly.
Common Speed Conversions
| From | To | Equivalent |
|---|---|---|
| 1 mph | km/h | ≈ 1.609 km/h |
| 1 knot | mph | ≈ 1.15 mph |
| 1 km/h | m/s | ÷ 3.6 |
| 1 knot | km/h | 1.852 km/h |
Why Knots Rule the Sea and Sky
A knot is one nautical mile per hour, and a nautical mile equals exactly one minute of latitude. That elegant relationship means a navigator can read distance and speed directly off a chart's latitude lines. It's why aviation and maritime navigation stick with knots while the rest of the world uses mph and km/h.
A Handy Mental Shortcut
For a quick mph-to-km/h estimate, add about 60% — the factor is roughly 1.6. So 50 mph is about 80 km/h, and 70 mph is about 112. It's close enough for reading road signs at a glance, and the converter supplies the exact figure when you need precision.
Who Uses a Speed Converter
- Drivers reading speed limits abroad.
- Runners and cyclists tracking pace across units.
- Sailors and pilots working in knots.
- Students converting to m/s for physics.
Accurate and Free
The converter uses exact factors at full precision, all in your browser. Convert as often as you need, free.
Frequently Asked Questions
How do I convert mph to km/h?
Multiply miles per hour by about 1.609. For example, 60 mph is about 97 km/h. This is the most common speed conversion for drivers crossing between imperial and metric countries.
How fast is one knot?
One knot is one nautical mile per hour, equal to about 1.15 mph or 1.852 km/h. Knots are used in aviation and at sea because a nautical mile relates directly to lines of latitude on a chart.
How do I convert km/h to m/s?
Divide kilometers per hour by 3.6 to get meters per second. For example, 36 km/h is 10 m/s. Meters per second is the standard unit in physics, so this conversion comes up often in science.
Why are knots used in aviation and sailing?
A nautical mile equals one minute of latitude, so speed in knots maps neatly onto navigation charts and distances over the globe. This makes knots more practical than mph or km/h for plotting courses.
What is a quick mph-to-km/h estimate?
A rough trick is to add about 60% to the mph figure, since the factor is roughly 1.6. So 50 mph is about 80 km/h. The converter gives the exact value when precision matters.
What units does this support?
It handles miles per hour (mph), kilometers per hour (km/h), meters per second (m/s), and knots, covering driving, running, sailing, aviation, and physics in one tool.
Is the conversion accurate?
Yes. It applies exact factors at full precision, so results are reliable for navigation and scientific work alike.
Is this tool free?
Yes — free, instant, and unlimited, with no signup.