The Complete Guide to Speed Conversions

Everything you need to convert speed units lives on this page: definitions of each unit, exact conversion factors, mental-math shortcuts, and complete tables between the most-used pairs.

Prefer a calculator? Every conversion on this page has an instant, free tool — start at the tools hub or use the links under each unit below.

The units at a glance

Meter per second (m/s)

Meters per second is the SI speed unit used in physics and meteorology — a brisk walk is about 1.5 m/s, a sprinter peaks near 12 m/s.

• 1 m/s = 3.6 kilometers per hour (km/h) — Meter per second to Kilometer per hour converter
• 1 m/s = 2.2369 miles per hour (mph) — Meter per second to Mile per hour converter
• 1 m/s = 1.9438 knots (kn) — Meter per second to Knot converter
• 1 m/s = 3.2808 feet per second (ft/s) — Meter per second to Foot per second converter

Kilometer per hour (km/h)

Kilometers per hour is the road-speed unit of most of the world; 100 km/h is the classic highway limit, equal to about 62 mph.

• 1 km/h = 0.277778 meters per second (m/s) — Kilometer per hour to Meter per second converter
• 1 km/h = 0.621371 miles per hour (mph) — Kilometer per hour to Mile per hour converter
• 1 km/h = 0.539957 knots (kn) — Kilometer per hour to Knot converter
• 1 km/h = 0.911344 feet per second (ft/s) — Kilometer per hour to Foot per second converter

Mile per hour (mph)

Miles per hour governs road speeds in the US and UK. One mph is exactly 1.609344 km/h.

• 1 mph = 0.44704 meters per second (m/s) — Mile per hour to Meter per second converter
• 1 mph = 1.6093 kilometers per hour (km/h) — Mile per hour to Kilometer per hour converter
• 1 mph = 0.868976 knots (kn) — Mile per hour to Knot converter
• 1 mph = 1.4667 feet per second (ft/s) — Mile per hour to Foot per second converter

Knot (kn)

The knot — one nautical mile per hour — is the speed unit of ships, aircraft and wind. It ties neatly to navigation because one nautical mile is one minute of latitude.

• 1 kn = 0.514444 meters per second (m/s) — Knot to Meter per second converter
• 1 kn = 1.852 kilometers per hour (km/h) — Knot to Kilometer per hour converter
• 1 kn = 1.1508 miles per hour (mph) — Knot to Mile per hour converter
• 1 kn = 1.6878 feet per second (ft/s) — Knot to Foot per second converter

Foot per second (ft/s)

Feet per second appears in ballistics, sports science and engineering specs — 88 ft/s is exactly 60 mph, a ratio American engineers memorize.

• 1 ft/s = 0.3048 meters per second (m/s) — Foot per second to Meter per second converter
• 1 ft/s = 1.0973 kilometers per hour (km/h) — Foot per second to Kilometer per hour converter
• 1 ft/s = 0.681818 miles per hour (mph) — Foot per second to Mile per hour converter
• 1 ft/s = 0.592484 knots (kn) — Foot per second to Knot converter

Every conversion formula

The table below lists the exact formula for every speed pair we support. All factors derive from the SI definitions of the units, so chaining them never introduces error.

One-line cross reference: every unit in every other unit

The complete pairwise reference — every supported speed unit expressed in each of the others:

• 1 meter per second = 3.6 kilometers per hour
• 1 meter per second = 2.2369 miles per hour
• 1 meter per second = 1.9438 knots
• 1 meter per second = 3.2808 feet per second
• 1 kilometer per hour = 0.277778 meters per second
• 1 kilometer per hour = 0.621371 miles per hour
• 1 kilometer per hour = 0.539957 knots
• 1 kilometer per hour = 0.911344 feet per second
• 1 mile per hour = 0.44704 meters per second
• 1 mile per hour = 1.6093 kilometers per hour
• 1 mile per hour = 0.868976 knots
• 1 mile per hour = 1.4667 feet per second
• 1 knot = 0.514444 meters per second
• 1 knot = 1.852 kilometers per hour
• 1 knot = 1.1508 miles per hour
• 1 knot = 1.6878 feet per second
• 1 foot per second = 0.3048 meters per second
• 1 foot per second = 1.0973 kilometers per hour
• 1 foot per second = 0.681818 miles per hour
• 1 foot per second = 0.592484 knots

Real-world reference points

Speed anchors: a brisk walk is 5 km/h (3.1 mph), a sprinting human peaks near 45 km/h, city speed limits cluster around 50 km/h / 30 mph, highway cruise is 100–130 km/h / 60–80 mph, and a commercial jet cruises at about 900 km/h (490 knots).

Most-used conversion tables

Kilometer per hour to Mile per hour

Knot to Mile per hour

Meter per second to Kilometer per hour

Kilometer per hour to Meter per second

Mile per hour to Kilometer per hour

Mile per hour to Knot

Knot to Foot per second

Foot per second to Knot

Common mistakes to avoid

Speed conversions go wrong when drivers mentally swap km/h and mph limits while traveling (a 100 km/h limit is only 62 mph), and when knots are treated as land miles per hour — a knot is based on the longer nautical mile, so 500 knots is 575 mph, not 500.

Tips for accurate conversions

• Round once, at the end. Chaining conversions and rounding each step compounds error surprisingly fast.
• Watch for regional unit variants. Some unit names have US and imperial variants with different sizes — always check which one your source means.
• Estimate first, then compute. A rough mental figure catches order-of-magnitude mistakes before they end up in your work.
• Use exact factors for anything official. The factors in this guide are the internationally defined values, not approximations.

Frequently asked questions

Which speed unit should I use?

Use the unit your audience expects: metric units for international and scientific audiences, US customary units for American everyday contexts. When in doubt, give both — "5 km (3.1 mi)" style.

Are these conversion factors exact?

Yes. Every factor on this page comes from the internationally agreed definition of the units involved (most were fixed by treaty in 1959 or by SI definition), so the only inaccuracy is the rounding you choose for the final answer.

Can I use these tables offline?

Yes — print this page or save it as a PDF. The tables are computed from exact factors and will not go out of date.