Speed Calculator — Distance, Speed, Time
Calculate speed, distance, or time from the other two values. Supports mph, km/h, m/s with unit conversion between all common speed, distance, and time units. See also our Gas Mileage Calculator and Time Calculator.
How to Calculate Speed, Distance, or Time
- Select what you want to solve for: speed, distance, or time.
- Enter the two known values with their units.
- Click Calculate to get the result in your chosen unit.
- View conversions to all other common units.
Formula
Speed = Distance / Time
Distance = Speed × Time
Time = Distance / Speed
Unit Conversions:
1 mph = 1.60934 km/h = 0.44704 m/s
1 mile = 1.60934 km = 5280 feet
1 hour = 60 minutes = 3600 secondsExample
A car travels 150 miles in 2.5 hours. What is its speed?
Speed = 150 miles / 2.5 hours = 60 mph
= 96.56 km/h = 26.82 m/s = 88.00 ft/s
Speed Conversion Reference Table
| mph | km/h | m/s | knots |
|---|---|---|---|
| 10 | 16.09 | 4.47 | 8.69 |
| 30 | 48.28 | 13.41 | 26.07 |
| 60 | 96.56 | 26.82 | 52.14 |
| 75 | 120.70 | 33.53 | 65.17 |
| 100 | 160.93 | 44.70 | 86.90 |
| 120 | 193.12 | 53.64 | 104.28 |
Frequently Asked Questions
What is the formula for speed?
Speed equals distance divided by time (S = D/T). This gives average speed over the entire journey.
How do I convert mph to km/h?
Multiply mph by 1.60934 to get km/h. For example, 60 mph = 96.56 km/h.
What is the difference between speed and velocity?
Speed is a scalar (magnitude only), while velocity is a vector (magnitude and direction). This calculator computes speed (scalar).
How do I calculate travel time?
Divide distance by speed. For example, 300 miles at 60 mph takes 300/60 = 5 hours.
What is a knot?
A knot is one nautical mile per hour (1.852 km/h or 1.151 mph). It is used in aviation and maritime navigation.