Speed Converter
km/h to m/s, mph to km/h & the 5/18 rule explained
Convert speed units instantly โ kilometers per hour to meters per second, meters per second to km/h, miles per hour to km/h and knots โ with the 5/18 rule explained step by step, not just stated.
Convert speed now โ free
km/h, m/s & mph โ Quick Answers
The exact conversions people search for most, answered directly.
| Value | Equals |
|---|---|
| 36 km/h | 10 m/s |
| 36 km/h | 22.37 mph |
| 3.6 km/h | 1 m/s |
| 5 km/h | 1.389 m/s |
| 18 mph | 28.97 km/h |
| 1 m/s | 3.6 km/h |
| 1 km/h | 0.6214 mph |
| 100 km/h | 62.14 mph |
| 60 mph | 96.56 km/h |
| 1 knot | 1.852 km/h |
Have a different number? Type it into the calculator above for an instant answer.
Worked Examples
See exactly how each conversion is calculated, step by step โ including where the famous 5/18 rule actually comes from.
Derive the 5/18 rule used to convert km/h to m/s.
- 1 km/h = 1,000 m per 3,600 s
- 1,000 รท 3,600 = 5/18 (simplified fraction)
- So km/h ร 5/18 = m/s, and m/s ร 18/5 = km/h
Convert 36 km/h to m/s.
- Multiply by 5/18
- 36 ร 5 รท 18
- = 180 รท 18
Convert 36 km/h to mph.
- 1 km/h โ 0.6214 mph
- Multiply by 0.6214
- 36 ร 0.6214
Convert 18 mph to km/h.
- 1 mph = 1.609344 km/h
- Multiply by 1.609344
- 18 ร 1.609344
Try any of these with the shortcut chips in the calculator above, or swap in your own numbers.
Free Speed Converter โ km/h to m/s, mph to km/h & more
Converting between speed units comes up constantly in physics homework โ turning a car's speed in km/h into m/s for a formula, checking a race speed in mph, or working through a motion numerical that mixes metric and imperial units. This speed converter is built to make that instant, accurate, and free, with no signup, no app download and no ads getting in the way.
It covers the speed conversions people search for most: km/h to m/s, m/s to km/h, mph to km/h, km/h to mph and m/s to mph โ plus knots and feet per second, so you can move between the units used in physics, aviation and everyday contexts in one place instead of hunting for a separate tool for each pair.
The one conversion worth actually understanding rather than memorising is the 5/18 rule: since 1 km = 1,000 m and 1 hour = 3,600 s, 1 km/h works out to 1,000 รท 3,600 m/s, which simplifies to exactly 5/18 m/s. That's why km/h ร 5/18 gives m/s, and the reverse โ m/s ร 18/5 (the same as ร3.6) โ gives km/h back. Knowing where the fraction comes from makes it much easier to remember under exam pressure than memorising "multiply by 5/18" as a bare fact.
Every conversion uses standard SI conversion factors โ the same values accepted in TN Board, CBSE, NEET and JEE numericals โ so the result you get here is the exact figure examiners expect, not a rounded approximation. That makes this tool useful for more than just homework: physics students converting velocity in motion problems, competitive exam aspirants solving numericals under time pressure, and anyone who needs a quick, reliable speed conversion can rely on the same formulas used in this converter.
Just pick your from and to units (or tap one of the shortcut chips above), type in your value, and the result updates instantly โ no "convert" button to click, no page reload, no waiting. Working on a full kinematics problem instead of a single conversion? The speed, distance and time calculator solves for any one of the three given the other two.
โ Back to all unit convertersSpeed conversion โ common questions
Multiply the value in km/h by 5/18 (or divide by 3.6). For example, 36 km/h ร 5/18 = 10 m/s.
Because 1 km/h means 1,000 metres every 3,600 seconds. Dividing 1,000 by 3,600 gives exactly 5/18. So multiplying a km/h value by 5/18 converts it to m/s, and multiplying an m/s value by 18/5 (its reciprocal) converts it back to km/h.
Multiply the value in m/s by 18/5 (or by 3.6). For example, 10 m/s ร 3.6 = 36 km/h.
Multiply the value in mph by 1.6093. For example, 60 mph ร 1.6093 โ 96.56 km/h.
Multiply the value in km/h by 0.6214. For example, 100 km/h ร 0.6214 โ 62.14 mph.
1 knot equals approximately 1.852 km/h. Knots are commonly used to measure speed in aviation and at sea.
Yes โ it uses standard SI conversion factors (the same values accepted in TN Board, CBSE, NEET and JEE numericals), so results match what's expected in exam answers.