Running Pace Calculator
Pace, time or distance โ enter two, get the third, with race splits.
About this calculator
Every pace question is the same triangle: pace ร distance = time. Enter any two sides and this calculator gives the third, in min/km or min/mile, with cumulative splits you can read at each marker. Presets fill the exact race distances โ 5K, 10K, half marathon (21.0975 km) and marathon (42.195 km).
Using it for race day
The classic uses: turn a goal time into the pace you must hold (a 4-hour marathon is 5:41/km โ write it on your wrist), turn a training pace into a predicted finish, or make sense of a GPS watch's average. Two honest notes runners learn the hard way: race courses measure slightly long in practice (you run the tangents imperfectly), so bank a couple of seconds per kilometre under goal pace; and an even or slightly negative split โ second half no slower than the first โ beats a fast start in essentially every finishing-time study. The splits table gives you the checkpoint numbers to enforce it.
Frequently asked questions
What pace do I need for a 4-hour marathon?
5:41 per kilometre, or 9:09 per mile. The half in 2:00 needs the same pace โ which is why a recent half time is the best marathon predictor.
What's a good 5K pace for a beginner?
Finishing at all beats any number, but 7:00-8:00/km (35-40 min) is a common first-race range, and breaking 30 minutes (6:00/km) is the classic first big milestone.
Should I run even splits?
Yes โ or slightly negative (second half faster). Fast starts feel free and cost double later; the splits table gives you per-km checkpoints to hold yourself to.
Why was my GPS pace different from the official result?
GPS wobble and imperfect tangents make watches read courses long โ typically 0.5-1% โ so official pace is slightly slower than watch pace for the same run. Bank a few seconds per km under goal pace to cover it.