Speed Converter — Calculator

About speed conversions

Speed is distance divided by time, so every unit here is a length unit over a time unit. The SI unit is the meter per second; road speeds are given in kilometers per hour in Tanzania and most countries, and in miles per hour in the United States and UK.

Knots belong to navigation rather than the road. One knot is one nautical mile per hour, and a nautical mile is one minute of latitude — which is what makes knots convenient on charts and in the air. Wind speeds, marine forecasts and aviation all use them.

Road speeds and vehicle limits (km/h or mph).
Wind and weather reports (m/s, km/h or knots).
Shipping and aviation (knots).
Physics and engineering (m/s).

Reading the answers. The 3.6 factor between m/s and km/h is exact, so those two convert losslessly. Knots and miles per hour are exact definitions as well.

The units in this converter

What each unit is and where it is normally used. Everything here is converted through the meters per second.

Meters per second (m/s): The meter per second is the SI unit of speed. It is used in science and engineering, where distances are in meters and time in seconds.
Kilometers per hour (km/h): A kilometer per hour is 0.277778 meters per second. It is the unit on road signs and vehicle speedometers in Tanzania and most countries.
Miles per hour (mph): A mile per hour is 0.44704 meters per second. It is the road-speed unit in the United States and the United Kingdom, and appears on imported vehicle speedometers.
Knots (kn): A knot is one nautical mile per hour, or 0.514444 meters per second. It is the standard unit for the speed of ships and aircraft.
Feet per second (ft/s): A foot per second is 0.3048 meters per second. It is used in aviation, engineering and wind-speed figures in imperial-measure countries.

Tanzania reference points

Real quantities in speed, shown in the units people actually use.

The speed limit in built-up areas in Tanzania
50 km/h · 13.888889 m/s · 31.06856 mph · 26.99784 kn · 45.567221 ft/s
Source: Road Traffic Act [Cap.168 R.E 2002] s.51, summarised by FB Attorneys · verified 2026-09-14
The maximum speed outside built-up areas for vehicles over 3,500 kg in Tanzania
80 km/h · 22.222222 m/s · 49.709695 mph · 43.196544 kn · 72.907553 ft/s
Outside built-up areas the limit for other vehicles is set by posted signs and road markings rather than a single national figure.
Source: Road Traffic Act [Cap.168 R.E 2002] s.51, summarised by FB Attorneys · verified 2026-09-14

Popular conversions

Miles per hour to Kilometers per hour Kilometers per hour to Miles per hour Meters per second to Kilometers per hour Kilometers per hour to Meters per second Knots to Kilometers per hour Miles per hour to Knots

Convert from any speed unit

Each unit has its own page with every other unit in the dimension, the exact factor for each, and worked values.

Meters per second converterm/s to 4 other speed units Kilometers per hour converterkm/h to 4 other speed units Miles per hour convertermph to 4 other speed units Knots converterkn to 4 other speed units Feet per second converterft/s to 4 other speed units

Frequently asked questions

How do I convert mph to km/h?

Multiply the miles-per-hour value by 1.609344 to get kilometers per hour.

How many km/h is one knot?

One knot equals exactly 1.852 km/h.

How do I convert km/h to m/s?

Divide the kilometers-per-hour value by 3.6 to get meters per second.

All speed conversions

Every speed conversion on Calculator, listed in full.