Average Speed Calculator

The average speed formula

Average speed tells you how fast you travelled over a whole journey, ignoring the ups and downs along the way. It is the total distance divided by the total time, no matter how often you sped up, slowed down or stopped.

average speed = total distance ÷ total time

Rearranged, the same relationship gives distance = speed × time and time = distance ÷ speed. If you know any two of the three quantities you can find the third with the speed, distance and time calculator.

The unit of the answer comes from the units you use. Miles divided by hours is miles per hour (mph), kilometres divided by hours is km/h and metres divided by seconds is m/s. This calculator converts for you, so you can enter, say, kilometres and read the result in mph as well.

How to use the calculator

1. Type the total distance and choose its unit: miles, km, yards, feet or meters.
2. Fill in the time taken in the h, m and s boxes. You can use any combination, and blank boxes count as zero.
3. Press the button to see the average speed. Distances in miles or km give two lines (mph and km/h). Meters, feet and yards also show the speed per hour in that unit, and meters and feet add the speed per second.

The time boxes are added together, so 90 minutes can be entered as 1 h 30 m or as 0 h 90 m, and 1.5 hours can be typed into the hours box directly. At least one of them must be above zero, otherwise no speed can be worked out.

Count every minute of the trip, including rest stops, if you want the average speed for the whole journey. Use only the time spent moving if you are after your moving average.

How to calculate average speed by hand

1. Add up the whole distance travelled, in one unit.
2. Convert the time to a single unit, usually hours: hours + minutes ÷ 60 + seconds ÷ 3600.
3. Divide the distance by the time.

Example 1. A driver covers 150 miles in 2 hours 30 minutes. The time is 2.5 hours, so the average speed is 150 ÷ 2.5 = 60 mph. In metric units that is 60 × 1.609344 = 96.56 km/h.

Example 2, with seconds. A cyclist rides 12 km in 1 h 5 min 30 s. The time is 1 + 5/60 + 30/3600 = 1.091667 h, so the average speed is 12 ÷ 1.091667 = 10.99 km/h.

Example 3, short distance. A sprinter runs 500 meters in 45 seconds. That is 500 ÷ 45 = 11.11 m/s, which is 40 km/h or 24.85 mph.

Why you cannot just average two speeds

It is tempting to add speeds and divide by two, but that only works if you spent equal time at each speed. If you cover equal distances at different speeds, you spend longer at the slow one, so it counts for more.

Example. You drive 60 km at 40 km/h, which takes 1.5 hours, then another 60 km at 60 km/h, which takes 1 hour. The total is 120 km in 2.5 hours, so the average speed is 120 ÷ 2.5 = 48 km/h, not the 50 km/h you would get from (40 + 60) ÷ 2.

average speed for two equal distances = 2 × v₁ × v₂ ÷ (v₁ + v₂)This is the harmonic mean of the two speeds: 2 × 40 × 60 ÷ 100 = 48.

The safe approach is always to add up distances and times first, then divide.

Average speed versus average velocity

Speed only cares about how much ground you covered. Velocity also has a direction, and average velocity is the displacement (the straight-line change in position from start to finish) divided by time.

Example. A runner completes one 400 m lap of a track in 80 seconds. The average speed is 400 ÷ 80 = 5 m/s (18 km/h), but because the runner finishes where they began, the displacement is zero and the average velocity is 0 m/s.

For a straight trip in one direction the two numbers are equal in size. When you need to know how quickly speed itself is changing, use the acceleration calculator; for running and walking, pace (time per mile or kilometre) is the usual way to express the same idea.

Handy speed conversions

Highway limits are quoted in different units around the world. These conversions use 1 mph = 1.609344 km/h and 1 mph = 1.466667 ft/s (5,280 ft ÷ 3,600 s).

For any other value, use the speed converter.