Pace Percentage Calculator
Training plans love saying things like "6 × 1K at 95% of 5K pace" — and leave the math to you. Enter the percentage and your race pace to get the exact split, or flip it to find what race pace a workout implies.
Your percentage cheat sheet
Every common training percentage of . Notes assume the reference is 5K race pace.
| % | Pace | Typical use |
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How this calculator works
This tool uses percent of pace, the convention used in elite distance coaching (most famously by Renato Canova's marathon programs). Every percentage point below 100 adds exactly 1% of the reference pace:
- 95% of 5:00/mi → add 5% of 5:00 (15 s) → 5:15/mi
- 90% of 5:00/mi → add 10% (30 s) → 5:30/mi
- 105% of 5:00/mi → subtract 5% (15 s) → 4:45/mi — faster than race pace
That is not the same thing as percent of speed. Taking 90% of the speed behind 5:00/mi gives 5:33/mi, not 5:30 — and the steps get lopsided as paces change. Percent of pace keeps every 5% jump the same number of seconds, which is why coaches write workouts this way and why we use it here. (Sports-science papers usually use percent of speed, so don't mix the two when reading research.)
Percentages also beat "add 20 seconds per mile" rules: additive rules break for very fast and very slow runners, while percentages scale with the athlete. If you want to go deeper, the concept is explored thoroughly at Running Writings, whose calculator inspired this one.
The 5% rule
A handy companion to percentage training: a well-trained runner slows roughly 5% for each doubling of race distance. That gives you quick anchors, all relative to 5K pace:
- 10K ≈ 95% of 5K pace
- Half marathon ≈ 90% of 5K pace
- Marathon ≈ 95% of half-marathon pace (≈ 85% of 5K — treat this one loosely)
- Critical speed ≈ 95%, lactate threshold ≈ 91–92%, aerobic threshold ≈ 85% of 5K pace
These are population averages — your mileage may literally vary. Use them as starting points and let effort and results fine-tune the numbers.
FAQ
What does "95% of 5K pace" actually mean?
Run 5% slower than your 5K race pace, measured in pace: 5:00/mi becomes 5:15/mi. Each point below 100% adds an equal time step — 90% is 5:30, 85% is 5:45 — which makes workout paces easy to compute and evenly spaced.
Why does my result differ from a "percent of speed" calculator?
Because the math is genuinely different: percent of pace adds time linearly, percent of speed divides distance-per-minute. At 90% the two disagree by a few seconds per mile, and the gap grows the further you get from 100%. Workouts written by coaches almost always mean percent of pace.
When would I use reverse mode?
When a workout tells you about your fitness. Say you cruised 5 miles at 90% effort averaging 5:24/mi — reverse mode shows what 5K race pace that performance implies, which is handy for updating training paces mid-season without racing.