CalcKit
Speed, Distance & Time Calculator
Table of Contents
- Speed, distance and time
- The speed, distance and time formula
- The speed, distance and time triangle
- Examples
- Average speed
- Frequently asked questions
Speed, distance and time
Speed is how far something travels in a given time. Speed, distance and time are tied together by one simple relation, so knowing any two of them gives the third: how fast a train went, how far a cyclist rides in 40 minutes, or how long a drive will take.
Enter any two of speed (v), distance (d) and time (t), each in the unit you have, and the calculator finds the third. It works with the average speed, as if the speed were the same for the whole trip, and also shows the time in hours, minutes and seconds.
To change a speed from one unit to another, use the Speed Converter; for running paces in minutes per kilometre or mile, the Pace Converter.
The speed, distance and time formula
Speed is distance divided by time:
v = d / t
The three parts mentioned in this tool are speed (v), distance (d) and time (t). Some school books write speed as s; the formula is the same, s = d / t.
The units have to match: kilometres and hours give km/h, metres and seconds give m/s. The calculator converts for you, so a distance in miles and a time in minutes still give a speed in km/h, mph or knots.
Speed (v)
Speed is the distance covered per unit of time: kilometres per hour (km/h), metres per second (m/s), miles per hour (mph), knots (nautical miles per hour) or feet per second (ft/s).
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If you know the distance and the time:
v = d / t
Distance (d)
Distance is how far the object travels: in kilometres, metres, miles, feet, yards or nautical miles.
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If you know the speed and the time:
d = v * t
Time (t)
Time is how long the trip takes: in hours, minutes, seconds or days.
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If you know the distance and the speed:
t = d / v
Time in hours, minutes and seconds
A time worked out as t = d / v usually comes out as a decimal, such as 2.75 hours. In the background, the calculator works out the time in seconds, t * 3600 for a time in hours, and splits it into the whole hours, the whole minutes left over and the seconds left over. So 2.75 hours is shown as 2 hours, 45 minutes and 0 seconds, and a time typed as 105 minutes as 1 hour and 45 minutes.
The speed, distance and time triangle
The speed distance time triangle is a way to remember the three formulas. Draw a triangle with a line across it: d sits at the top, with v and t side by side below the line. Cover the one you want to find, and the other two show how to work it out:
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Cover d: v and t are side by side, so multiply them:
d = v * t -
Cover v: d is over t, so divide:
v = d / t -
Cover t: d is over v, so divide:
t = d / v
Examples
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Speed: a train covers 210 km in 1 hour 45 minutes, which is 1.75 hours.
v = 210 / 1.75 = 120 km/h -
Time: a 150-mile drive at an average of 60 mph.
t = 150 / 60 = 2.5 h, which is 2 hours 30 minutes -
Distance: a cyclist rides at 18 km/h for 40 minutes, which is
40 / 60of an hour.d = 18 × 40 / 60 = 12 km -
Metres per second: a sprinter runs 100 m in 9.58 seconds.
v = 100 / 9.58 = 10.4384 m/s, which is 37.5783 km/h -
Knots: a boat sails 30 nautical miles at 12 knots.
t = 30 / 12 = 2.5 h, which is 2 hours 30 minutes
Average speed
The average speed of a trip is the total distance divided by the total time, stops included:
average speed = total distance / total time
It is not the average of the speeds. Drive 60 km at 60 km/h, which takes 1 hour, then another 60 km at 120 km/h, which takes 30 minutes: that is 120 km in 1.5 hours, an average of 80 km/h, not 90 km/h. To find the average speed of a trip here, enter its total distance and total time.
Frequently asked questions
How do you calculate speed?
Divide the distance by the time. A car that travels 150 km in 2 hours has an average speed of 75 km/h:
v = 150 / 2 = 75 km/h
For a speed per hour, give the time in hours: 30 minutes is 0.5 hours.
How do you calculate time from distance and speed?
Divide the distance by the speed. At 80 km/h, 200 km takes 2.5 hours, which is 2 hours 30 minutes:
t = 200 / 80 = 2.5 h
What is the difference between speed and velocity?
Speed is how fast something moves. Velocity is speed in a given direction, so a car going round a bend at a steady 50 km/h keeps its speed but changes its velocity. For a trip in a straight line in one direction, the two are the same number, which is why physics writes speed as v too.
How do you convert km/h to m/s?
Divide by 3.6, since 1 km/h is 1000 metres in 3600 seconds. So 72 km/h is 20 m/s:
72 / 3.6 = 20 m/s
To go back from m/s to km/h, multiply by 3.6.