About the Speed Distance Time Calculator
This speed distance time calculator solves the classic triangle d = s × t for whichever value you are missing. Pick what you want to find, enter the other two, and it returns the answer along with conversions to km and miles, km/h, mph and m/s, plus the matching running or cycling pace per kilometre and per mile.
Use it to answer "how long will it take to drive 250 km at 90 km/h?", to work out your average speed from a GPS track or race time, to plan a sailing passage in nautical miles and knots, or to check physics homework. The chart shows distance covered over the trip and the table shows how the travel time changes at slower and faster speeds.
The calculator assumes a constant average speed. Real journeys include stops, traffic, climbs and acceleration, so for trip planning treat the answer as moving time and add breaks on top.
How to use the speed distance time calculator
- 1Choose whether to solve for time, distance or speed.
- 2Enter the two values you know and pick their units.
- 3Enter time as hours, minutes and seconds.
- 4Read the answer and the conversions to other units and pace.
- 5Check the table to see how a faster or slower speed changes the time.
Formula and method
Distance, speed and time are linked by one relationship, d = s × t, which can be rearranged to solve for any one of them. The only trap is units: they must match, so the calculator converts everything to metres, metres per second and seconds internally, solves, and converts the answer back to the units you chose.
The speed here is an average over the whole trip. Pace is the inverse of speed – time per unit distance – and is shown per kilometre and per mile because runners and walkers usually think in pace. One mile is exactly 1,609.344 m, one nautical mile 1,852 m, and one knot one nautical mile per hour.
- d
- Distance
- s
- Average speed
- t
- Time
Worked examples
How long to drive 250 km at 90 km/h?
t = 250 ÷ 90 = 2.778 hours = 2 h 46 min 40 s of moving time, before any stops.
Distance in 2 h 15 min at 65 mph
d = 65 × 2.25 = 146.25 miles, which is 235.4 km.
Average speed for a 10 km run in 47:30
s = 10 ÷ (47.5/60) = 12.63 km/h (7.85 mph). Pace is 2,850 s ÷ 10 = 285 s = 4:45 per km.
Marathon in 3 h 30 min
42.195 ÷ 3.5 = 12.06 km/h. 12,600 s ÷ 42.195 = 298.6 s ≈ 4:59 per km, and ÷ 26.22 miles ≈ 8:01 per mile.
Sailing 120 nautical miles at 15 knots
A knot is one nautical mile per hour, so t = 120 ÷ 15 = 8 hours. 120 nmi × 1.852 = 222.24 km.
Frequently asked questions
What is the formula for speed, distance and time?+
Distance = speed × time. Rearranged, time = distance ÷ speed and speed = distance ÷ time. Make sure the units agree, for example km with km/h and hours, before dividing or multiplying.
How do I calculate average speed?+
Divide the total distance by the total time, including any slow sections. Do not simply average the speeds of different legs: 60 km/h out and 40 km/h back over the same distance averages 48 km/h, not 50.
How do I convert decimal hours into hours and minutes?+
Keep the whole number as hours and multiply the decimal part by 60 for minutes. For example 2.778 hours is 2 hours plus 0.778 × 60 = 46.7 minutes, or 2 h 46 min 40 s.
What is the difference between speed and pace?+
Speed is distance per unit time (km/h or mph); pace is time per unit distance (minutes per km or mile). Runners use pace; 12 km/h is the same as a 5:00 per km pace.
How long does it take to travel 100 miles?+
At 60 mph it takes 1 hour 40 minutes, at 70 mph about 1 hour 26 minutes, and at 50 mph 2 hours. Divide 100 by your average speed to get hours.