Training pace zones calculator
One recent 5K is enough to price every kind of run. Type it in and get your five pace zones — where easy really is, where threshold starts, and the pace your intervals should sit at — in both units.
| Zone | Target | Band | Feels like |
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How to use this
Type a 5K you ran hard in the last few months. The result is a ladder of five zones, each with a target pace and the band either side of it, in minutes per kilometre with the per-mile figure beside it. Pick the length of the run you are about to do and the ladder shifts slightly, because the pace you could race over 21 km is not the pace you could race over 5.
The number most runners get wrong is the first one. Zone 2 — easy, aerobic, conversational — should hold most of your weekly kilometres, and it is slower than almost everyone expects. If the easy pace here is a minute or more slower than what you call easy, your easy runs have been Zone 3, and that is where tired legs on session day come from.
What each zone is for
Zone 1, recovery, is the day after a hard session or a race: a jog with no purpose beyond blood flow. Zone 2, aerobic, builds the engine — the long run, the easy runs, the bulk of any plan. Zone 3, tempo, is comfortably hard, close to marathon effort, the pace of a steady run with a purpose. Zone 4, threshold, is the fastest pace you can hold for about an hour, and the most productive hard session for most distance runners. Zone 5, max effort, is 5K race pace and quicker, run in intervals with recovery between.
Why Zone 2 moves and the others barely do
Easy running sits at about seventy per cent of your aerobic capacity whatever your ability. Race intensity does not: a 15-minute 5K is run at a higher share of capacity than a 35-minute one, simply because it is over sooner. So the ratio between easy pace and 5K pace is wider for a quick runner and narrower for a slower one, and the easy zone here is priced that way rather than with one flat multiplier. The tempo, threshold and interval zones sit much closer to race pace, so the same effect moves them by only a few seconds.
Where these numbers come from
The zones are the ones the Outrunr app uses before a run (to set the target) and after it (to say which zone you actually ran in), ported to this page and pinned to the app's own test fixtures so the two cannot disagree. Race pace at a longer distance follows the same pace-decay rule as the race time predictor. The zone targets are shares of that race pace, with the easy share derived from the share of aerobic capacity a 5K of your time demands, and the band edges sit halfway between adjacent targets, so a pace on a target is squarely inside its zone. To turn a zone into a belt speed, the treadmill pace converter does the rounding.
Common questions
What are the five pace zones?
Zone 1 is recovery — a jog you could keep up all day. Zone 2 is aerobic or easy running, conversational, and where most of your weekly kilometres belong. Zone 3 is tempo: steady, comfortably hard, roughly marathon effort. Zone 4 is threshold, the fastest pace you can hold for about an hour. Zone 5 is maximal effort — intervals at and beyond 5K race pace. Each zone here comes with a target pace and the band around it.
Why is my easy pace so slow?
Because easy running sits at roughly seventy per cent of your aerobic capacity whoever you are, while a 5K is run at ninety per cent or more. The gap between the two is wide — about a third slower than 5K pace for a 20-minute runner, a little less for a slower one. Most runners run their easy days too fast, which is why they are tired for the sessions that matter. If the easy pace here feels embarrassingly slow, that is the point.
Why do the zones change when I pick a longer run?
Race pace is not one number. The pace you can hold for 5 km is quicker than the pace you can hold for a half marathon, by a predictable amount, so a zone defined as a share of race pace moves with the distance you are running. Picking the length of the run shifts the whole ladder slightly slower, which is what keeps a Zone 3 effort over 21 km from being a Zone 4 effort in disguise.
Should I train by pace or by heart rate?
Both describe the same effort from different sides. Pace is precise and immediate; heart rate lags, drifts in the heat and depends on sleep and caffeine. On flat ground with a recent race time, pace zones are the sharper tool. On hills, in heat, or when you have no recent race, heart rate is the honest one. The heart rate zone calculator gives you the other ladder, and the two should broadly agree on an easy day.
How recent does the 5K need to be?
Within the last two or three months, and run hard. A 5K from a year ago prices every zone off a fitness you may no longer have, or may have moved past; a 5K you jogged prices them too slow. If your only recent effort is a parkrun, the parkrun time calculator explains what one 5K can and cannot tell you.
Is anything stored?
No. The calculation runs in your browser. Nothing is sent anywhere and nothing is saved.
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Knowing your zones is step one. Running in the right one, on the right day, is the plan.
Outrunr builds your week around these zones, tells you which one today's run belongs in, and calls your pace in your ear when you drift out of it.