Pace, Distance and Time Are One Equation
Every running calculation is the same relationship seen from a different side: pace times distance gives time, time divided by distance gives pace. Knowing any two produces the third, which is what turns a training run into a prediction and a goal time into a pace you can hold in your head.
This calculator solves for whichever value you leave blank, in either minutes per kilometre or minutes per mile.
How to Use the Pace Calculator
Fill in two of the three fields and the calculator supplies the third.
- Choose your units, minutes per kilometre or minutes per mile, before entering anything, since the numbers are not interchangeable.
- To find your pace from a run you have done, enter the distance and the time.
- To find a finish time, enter the distance and the pace you expect to hold.
- To find how far you went, enter the time and the pace.
- For race planning, work backwards from the goal: enter the race distance and your target time to get the pace you need to sustain the whole way.
- Compare that pace with the table below to see what it implies at other distances, which is a quick sanity check on whether a goal is realistic.
Average Pace Versus Race Pace
A pace calculator gives you an average, and races are rarely run at an even one. Most runners drift slower in the second half, so a goal time based on holding your training pace exactly tends to be optimistic. The common advice is negative splits, running the second half slightly faster, precisely because it is hard, and starting a few seconds per kilometre slower than target costs less than blowing up at thirty kilometres.
Pace also does not transfer cleanly between distances. A pace you can hold for 5K is well beyond what you can hold for a marathon, and the drop is not linear: each doubling of distance typically costs somewhere around fifteen to twenty seconds per kilometre for a trained runner. The table below shows what a given pace implies across the standard distances.
Pace to Finish Time
What each pace produces at the four standard race distances, assuming it is held evenly throughout.
| Pace /km | Pace /mi | 5K | 10K | Half | Marathon |
|---|---|---|---|---|---|
| 4:00 | 6:26 | 20:00 | 40:00 | 1:24:24 | 2:48:48 |
| 4:30 | 7:14 | 22:30 | 45:00 | 1:34:57 | 3:09:54 |
| 5:00 | 8:03 | 25:00 | 50:00 | 1:45:32 | 3:31:04 |
| 5:30 | 8:51 | 27:30 | 55:00 | 1:56:05 | 3:52:10 |
| 6:00 | 9:39 | 30:00 | 1:00:00 | 2:06:38 | 4:13:16 |
| 6:30 | 10:28 | 32:30 | 1:05:00 | 2:17:11 | 4:34:22 |
| 7:00 | 11:16 | 35:00 | 1:10:00 | 2:27:44 | 4:55:28 |
| 8:00 | 12:52 | 40:00 | 1:20:00 | 2:48:50 | 5:37:40 |
Half marathon is 21.0975 km and marathon 42.195 km, which is why the times are not exactly double. Treat these as even-pace figures, a real race almost always ends slower than it starts.
Using Pace in Training
Most training is meant to be slower than race pace, and the most common mistake in recreational running is doing easy runs too fast. Easy pace for a marathon runner is often a minute or more per kilometre slower than marathon pace, which feels wrong until you notice you are recovering enough to do the hard sessions properly.
Terrain, heat and altitude all change what a pace costs you. A hilly route at the same effort will read slower on the watch, and warm weather can cost twenty or thirty seconds per kilometre without anything being wrong. When conditions vary, running by effort and checking pace afterwards is more useful than chasing a number in the moment.