Speed Conversion Cheat Sheet: mph, km/h, m/s & Knots Explained
September 17, 2026
The core conversion factors: 1 mph = 1.60934 km/h = 0.44704 m/s = 0.86898 knots. To convert any speed, multiply by the factor for the unit you want, or divide by the factor for the unit you're converting from.
Skip the math and get your answer instantly:
Open the Speed Calculator →Quick Conversion Table
Each row shows what one unit of speed equals in the other three columns.
| 1 unit of… | mph | km/h | m/s | knots |
|---|---|---|---|---|
| mph | 1 | 1.60934 | 0.44704 | 0.86898 |
| km/h | 0.62137 | 1 | 0.27778 | 0.53996 |
| m/s | 2.23694 | 3.6 | 1 | 1.94384 |
| knot | 1.15078 | 1.852 | 0.51444 | 1 |
Worked Conversion Example
To convert 100 km/h to mph, multiply by the km/h→mph factor: 100 × 0.62137 = 62.14 mph. To go the other way, convert 60 mph to km/h by multiplying by 1.60934: 60 × 1.60934 = 96.56 km/h.
How to Calculate Average Speed
Average speed is always total distance divided by total time: Speed = Distance / Time. Driving 150 miles in 2.5 hours gives an average speed of 150 / 2.5 = 60 mph.
A common mistake is averaging two speeds directly. If you drive equal distances at 60 mph and 40 mph, your average speed for the trip is not 50 mph — it's total distance divided by total time, and since you spend longer at the slower speed, the true average works out lower, around 48 mph. The simple average of two speeds is only correct when you spend equal time (not equal distance) at each one.
Where Knots Come From
A knot is one nautical mile per hour, and it's the standard speed unit in aviation and marine navigation because a nautical mile is defined to correspond to one minute of latitude — convenient for chart-based navigation. 1 knot = 1.15078 mph = 1.852 km/h.
Frequently Asked Questions
How do I convert mph to km/h?
Multiply the mph value by 1.60934. For example, 60 mph × 1.60934 = 96.56 km/h.
How do I convert m/s to km/h?
Multiply the m/s value by 3.6. For example, 10 m/s × 3.6 = 36 km/h.
What is a knot in mph?
1 knot equals 1.15078 mph. Knots are used in aviation and marine navigation rather than mph or km/h.
Is average speed the same as averaging my two speeds?
Only if you spend equal time at each speed. If you cover equal distances at two different speeds instead, the true average speed is lower than the simple average, because more time is spent at the slower speed — always use total distance divided by total time.
How do I calculate speed from distance and time?
Divide distance by time: Speed = Distance / Time. Keep the units consistent — miles and hours for mph, or kilometers and hours for km/h.