Speed Converter

Convert speed and velocity between km/h, mph, meters per second, knots and feet per second.

100% client-side · nothing is uploaded

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Quick answer

Speed is a free, private online tool that lets you convert speed between km/h, mph, meters per second, knots and feet per second. It runs entirely in your browser, so nothing you enter is uploaded to a server.

How to use the Speed

Enter the number you want to convert in the Value field.
Pick the unit you're converting From and the unit you want To.
Read the converted result, or use ⇅ to swap the two units.
Check the All units table to see your value expressed in every supported unit at once.

Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.

About Speed

Common speed units

Cars use km/h or mph, science uses m/s, aviation and sailing use knots (nautical miles per hour).

Key conversions

1 m/s = 3.6 km/h. 1 mph is about 1.609 km/h. 1 knot is about 1.852 km/h or 1.151 mph.

Where it helps

Converting vehicle speeds when travelling, reading weather wind speeds, and physics problems.

Frequently asked questions

How fast is 1 knot?

About 1.852 km/h or 1.151 mph.

mph to km/h?

Multiply by 1.609.

m/s to km/h?

Multiply by 3.6.

Understanding Speed in depth

How speed conversion works

Speed is distance divided by time, so its units combine a length unit with a time unit. Each unit is expressed relative to a base — metres per second — and the tool converts to and from that base. The handy anchor is that 1 m/s equals exactly 3.6 km/h, because there are 3600 seconds in an hour and 1000 metres in a kilometre.

The everyday units

Cars and road signs use km/h (most of the world) or mph (US and UK). Science and physics use m/s. Aviation and shipping use knots (nautical miles per hour). Each suits its domain, and converting between them is the daily reality of travel, navigation and engineering.

Conversions people look up

The most searched are mph to km/h (×1.609), km/h to mph (×0.621), knots to mph (×1.151) and m/s to km/h (×3.6). A useful mental shortcut: to roughly convert km/h to mph, multiply by 0.6; to go the other way, multiply by 1.6.

Knots and why they exist

A knot is one nautical mile per hour, and because a nautical mile equals one minute of latitude, speed in knots maps directly onto distance covered across the globe — which is why aircraft and ships have stuck with it. 1 knot is about 1.852 km/h or 1.151 mph.

Everyday uses

Convert vehicle speeds when driving abroad, interpret wind speeds in weather reports, work physics problems, and read boat or aircraft instruments. Everything is instant and client-side.