Pace is elapsed time divided by distance. It helps you understand a finish-time target, but it cannot establish whether that target suits your current fitness, the course or the conditions. Calculate the requirement first, then assess it separately.
Calculate pace using consistent units
Divide the total time in seconds by kilometres or miles, then convert the result back to minutes and seconds. Keep more precision in the calculation than on the watch display. For a pace of six minutes per kilometre, five kilometres takes 30 minutes before allowing for any difference between the measured course and your recorded distance.
Approximate even-paced examples are:
- 5K in 20:00: 4:00 per kilometre, or 6:26 per mile.
- 5K in 30:00: 6:00 per kilometre, or 9:39 per mile.
- Half marathon in 1:30:00: 4:16 per kilometre, or 6:52 per mile.
- Half marathon in 2:00:00: 5:41 per kilometre, or 9:09 per mile.
- Marathon in 4:00:00: 5:41 per kilometre, or 9:09 per mile.
The half-marathon calculations use 21.0975 kilometres and the marathon uses 42.195 kilometres. Values are rounded for display. Finishing under a time requires being faster than the exact average for that time; a rounded pace is not a guarantee.
Use splits without chasing every fluctuation
Separate current pace from average and lap pace. Course markers and official timing may differ from a GPS watch's measured distance. A momentary change in the display is not a reason to surge unsafely or assume the course is wrong.
For a negative split, the second half takes less time than the first. Write the two half-times down and check that they add to the intended finish. Whether that strategy is appropriate depends on the runner and course; this guide does not promise it is best for everyone.
A workout is not a race certificate
A Yasso-style 800-metre session cannot by itself prove a marathon result. Likewise, completing a few repetitions at four minutes per kilometre does not establish readiness for a continuous sub-20 5K. Look at the whole preparation, recovery and race demands with an appropriate coach or plan.
For a first sub-30 5K, sub-four marathon or another target, use the training-plan checklist to check the starting assumptions. Runwiv's planned ghost and gap features can display a comparison; they do not establish physiological readiness or certified race timing.