What your parkrun time actually says about you
A finish time on its own tells you very little. Age-graded, it tells you where you sit among every runner your age — and what you should be running in training.
| Distance | Time | Pace |
|---|
| Effort | Pace | What it is for |
|---|
How to read this
Most runners judge themselves against the clock, which punishes everyone who is not 28 years old. Age grading fixes that. It expresses your run as a percentage of the world-record standard for your exact age and sex, so a 23:00 at 52 and a 19:30 at 28 can finally be compared honestly.
The percentile then places that percentage among actual runners. It is worth saying plainly: everyone in that population already runs. Landing at the 50th percentile does not mean you are average among people — it means you are mid-pack among people who race.
The equivalent times are a ceiling, not a promise
They describe what your current aerobic fitness is worth at each distance if you were equally trained for it. Nobody is. The further the distance from the one you actually train for, the more the prediction drifts — and it always drifts the same way, because marathon performance depends on long-run endurance that a 5K does not build.
The training paces matter more than the ranking
Easy pace is the one most runners get wrong, and they get it wrong in the same direction: too fast. The easy pace below sits mid-band of Daniels' published range on purpose. If it feels slow, that is the point — it is the pace that lets you absorb the sessions that actually hurt.
Where these numbers come from
VDOT is the Daniels & Gilbert model: an oxygen cost curve for velocity, divided by the fraction of maximum a runner can hold for that duration. The age factors are the Fair (2024) 5 km running tables from Yale. The open standards are WMA 2025. The model is calibrated between 1500 m and the marathon, so it declines to answer outside that range rather than inventing a number.
This is the same code that runs inside the Outrunr app, ported to JavaScript and pinned to the app's own test fixtures, so the two cannot drift apart.
Common questions
What is age grading?
Age grading compares your time to the world-record standard for your age and sex, as a percentage. It is the only fair way to compare a 25-year-old man with a 60-year-old woman. Above 60% is a good club runner, 70% is regional class, and 80% is national class.
Where does the percentile come from?
Your age-graded percentage is placed against the distribution of a real running population. The median runner sits near 48%, which is derived from 736,928 filtered race results. The very bottom of the curve is extrapolated rather than measured, so a percentile under about 10 is the least reliable part of the scale.
What is VDOT?
VDOT is a performance-equivalent aerobic index from Jack Daniels and Jimmy Gilbert. It is not a lab VO2 max — it is the number that makes two runners who race the same come out the same, which is exactly what you need to prescribe training paces from.
Why are my equivalent times slower than I expect?
Equivalent times assume you are equally trained for every distance. Most people are not. A runner who only ever races 5K will usually run slower than their predicted marathon, because the prediction assumes the long-run endurance that goes with it.
Do I have to have run a parkrun?
No. Any recent, honest 5K effort works — a time trial, a race, or a hard solo run. The model needs a genuine effort, not a training run.
Is anything stored?
No. The calculation runs in your browser. Nothing is sent anywhere and nothing is saved.
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Now do something with it.
Outrunr turns exactly these numbers into a week-by-week plan, then coaches you through each session and shows you when the number moves.