Speed, Distance and Time Calculator

Solve for speed, distance or travel time from the other two, in km/h, mph, m/s, knots or ft/s, with time in hours, minutes and seconds and the matching pace.

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About this tool

What is the Speed, Distance and Time Calculator?

Pick the quantity you want (speed, distance or time), fill in the other two, and the speed distance time calculator gives the answer immediately. Speed can be in km/h, mph, m/s, knots or ft/s; distance in metres, kilometres, miles, feet, yards or nautical miles; and time is entered or shown as hours, minutes and seconds.

Every result is also converted into all the other units in two side tables, so one calculation tells you a speed in km/h, mph and knots at once, and the pace per kilometre and per mile is shown for runners, walkers and cyclists.

Switching the unknown keeps the value just calculated, so you can solve a trip time, then flip to speed and adjust it to see how much faster you would need to go.

  • Solve for speed, distance or time
  • km/h, mph, m/s, knots and ft/s; metric, imperial and nautical distances
  • Hours, minutes and seconds input and output
  • Pace per km and per mile
  • Full unit conversion tables; copy and share
Read the guide: Speed, Distance and Download Time: Getting Rates Right

How to use the Speed, Distance and Time Calculator

  1. Choose what to solve for: Speed, Distance or Time.
  2. Enter the two known values. Choose the unit beside each field; for time, fill in any of hours, minutes and seconds.
  3. Read the result, the time in h:mm:ss, and the pace per kilometre and per mile.
  4. Use the tables to read the same speed or distance in every other unit.
  5. Change the unknown to rework the trip; the value just calculated stays in its field.

Worked examples

Driving time for 350 km at 100 km/h

Input

Time; distance 350 km, speed 100 km/h

Output

3:30:00 (3.5 hours)

350 ÷ 100 = 3.5 h. At a more realistic 85 km/h average with stops, the same trip takes 4:07:04.

A two-hour marathon pace

Input

Speed; 42.195 km in 2:00:00

Output

21.098 km/h (13.11 mph), 2:50.6 per km, 4:34.6 per mile

Pace is the inverse of speed: 3600 s ÷ 21.098 km/h = 170.6 s per km.

A ship crossing

Input

Time; 300 nautical miles at 12 knots

Output

25:00:00 (1 day 1 hour)

Knots are nautical miles per hour, so 300 ÷ 12 = 25 h with no conversion needed.

How far in 45 minutes at 60 mph

Input

Distance; 60 mph, 0 h 45 min

Output

45 miles (72.42 km)

60 mph is a mile a minute, so 45 minutes covers 45 miles.

Background and insight

The relation is the definition of average speed: speed = distance ÷ time. Rearranged, distance = speed × time and time = distance ÷ speed. The only real difficulty is units, and that is where most errors happen: 90 minutes is 1.5 hours, not 1.3, and a speed in km/h must be divided by 3.6 to get metres per second.

The conversion factors are exact by definition. The international mile is 1,609.344 metres, the foot 0.3048 metres and the nautical mile 1,852 metres, so 1 mph = 1.609344 km/h and 1 knot = 1.852 km/h. A nautical mile was originally one minute of latitude, which is why ships and aircraft use knots: distances read straight off a chart.

The result is an average over the whole trip. Real journeys include acceleration, stops and changing limits, all of which are already inside a measured average speed. For planning a drive, a realistic average (often 15 to 25% below the posted limit on mixed roads) gives a far better arrival time than the limit itself.

Common use cases

  • Trip planning

    Estimate arrival times for drives, cycle tours or hikes from a realistic average speed.

  • Sailing and flying

    Work in knots and nautical miles for passage and flight planning.

  • Physics problems

    Solve and check average speed questions with mixed units.

  • Training

    Turn a target time over a distance into the speed and pace you need to hold.

Tips and limitations

  • Enter 1 h 30 min as hours 1 and minutes 30, not 1.3 hours.
  • Average speed over a round trip is not the average of the two speeds: 60 km/h out and 40 km/h back averages 48 km/h.
  • For running-specific splits and race predictions, the Pace Calculator goes further.
  • Speeds over the ground differ from airspeed or speed through water when there is wind or current.
  • Results are rounded for display; the copy function keeps more digits.

Frequently asked questions

What is the formula for speed, distance and time?

Speed = distance ÷ time, distance = speed × time, and time = distance ÷ speed. Make sure the units match: km with hours for km/h, or metres with seconds for m/s.

How do I calculate travel time?

Divide the distance by the average speed. 350 km at 100 km/h is 3.5 hours, which is 3 hours 30 minutes. Convert the decimal part of the hours by multiplying by 60.

How do I convert km/h to m/s?

Divide by 3.6. 36 km/h is 10 m/s. To go from m/s to km/h, multiply by 3.6.

How many km/h is a knot?

Exactly 1.852 km/h, because a knot is one nautical mile (1,852 m) per hour. It is about 1.151 mph.

How do I work out average speed for a whole trip?

Divide the total distance by the total time, including stops. Averaging the speeds of each leg gives the wrong answer unless every leg took the same time.

How do I convert speed to pace?

Pace is time per distance, the inverse of speed. 12 km/h is 60 ÷ 12 = 5 minutes per km. The calculator shows pace per km and per mile for every result.

Is there an in-depth guide to the Speed, Distance and Time Calculator?

Yes. “Speed, Distance and Download Time: Getting Rates Right” covers the background, how it works, common pitfalls and worked examples. Read the full guide.

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