Speed Converter

How to use

1. 1Type or paste a speed value, for example 60. The input also accepts a suffix like '60 mph' or '100 km/h'.
2. 2Pick a source unit (mph, km/h, m/s, ft/s, knots, Mach, or any other listed). The Source card highlights blue.
3. 3Read every other unit on the result cards, grouped by metric, imperial, marine, and scientific.
4. 4Use a quick-conversion preset (mph to kph, knots to mph, Mach to mph, etc.) to load a common pair instantly.
5. 5Adjust decimal places to 0, 2, 4, or 6 to match the precision your task needs, then click Copy on any card.

About this tool

Speed Converter turns any speed value into every other common speed unit at once, entirely in your browser. Type a number, pick a source unit, and the tool fills in miles per hour (mph), kilometers per hour (km/h), meters per second (m/s), feet per second (ft/s), inches per second (in/s), centimeters per second (cm/s), knots (nautical miles per hour), Mach (referenced to 343 m/s, the standard sea-level speed of sound at 15 °C), and the speed of light c (299792458 m/s exactly). Conversions are computed through a single canonical value in m/s using exact factors: 1 mph is 1609.344 / 3600 m/s, 1 km/h is exactly 5/18 m/s, 1 ft/s is exactly 0.3048 m/s, 1 knot is 1852 / 3600 m/s, and the international foot, mile, and nautical mile are taken at their exact SI definitions. The input field accepts both period and comma decimal separators and a unit suffix in any of the common spellings (mph, m/s, mps, km/h, kph, kmh, kn, knots, ft/s, fps, in/s, ips, mach, c), so pasting '60 mph' or '100 km/h' just works; if the suffix you typed does not match the currently selected source unit the tool surfaces a one-click swap so you do not silently get the wrong reading. Quick-conversion presets cover the highest-search-volume pairs at a tap: mph to kph, kph to mph, knots to mph, m/s to km/h, m/s to mph, ft/s to mph, Mach to mph, and knots to kph. A reference panel below shows real-world speeds (walking pace, US highway limit, EU motorway limit, world-record sprint, container-ship cruise, airliner cruise at altitude, rifle muzzle velocity, terminal velocity in free fall, ISS orbital speed, Earth's orbital speed, the speed of light) and lets you drop any of them into the input as a one-click sanity check. Decimal precision is configurable (0, 2, 4, or 6 places) and trailing zeros are trimmed so 1.5 reads as '1.5' not '1.500000'. Useful for converting cycling, running, sailing, and motorsport speeds, comparing US and metric speed limits, sanity-checking aviation altitudes and Mach speeds, working through physics homework, prepping engineering drawings that switch between m/s and ft/s, and any time you need an exact conversion without trusting a single-row online widget. All math runs locally on your device, so the values you type here never leave your browser.

Free to use. Works in your browser. No signup, no login.