Parkrun Predictor
Predict your parkrun time from recent race performances.
Enter MM:SS or H:MM:SS
Pick the distance your entered time best represents an all-out effort for — we'll extrapolate from that effort down to a 5K prediction.
10K · 10.0 km
Closer reference distances extrapolate more accurately — try 5K or 10K for the most reliable estimate, or a longer distance if that's what you actually race at.
Enter a distance and time above to predict your parkrun.
About the parkrun predictor
A recent training run or average pace can be used to estimate your parkrun (5K) time, which is then compared against your personal best and shown alongside an age-adjusted performance rating. A third mode, Target Time, works the other way round: enter the finish time you're chasing and get the pace you need to hold.
How predictions are calculated
Your input is converted to an equivalent 5K time using the Riegel formula, the same method behind the Race Time Predictor, adjusted for the specific distance and effort of your training run.
Setting a goal pace
The Target Time tab reverses the calculation: enter the finish time you're chasing and it returns the even pace per km needed to hit it over the full 5K, along with the age-grade rating that time would earn. Since parkrun is always exactly 5K, this is a direct pace-from-time calculation rather than a Riegel-based prediction, so there's no reference distance to choose and no PB comparison shown for this mode.
How the age-adjusted rating works
Your time is expressed as a proportion of the age-adjusted world standard for your age and gender, using the WMA/Alan Jones age-factor tables. This lets you compare performances fairly across different ages: a 65-year-old and a 25-year-old running the same time can have very different ratings once age is accounted for.
Worked example
A 21:00 5K from a 30-year-old male compares against the male open-class standard of 12:49 (769 seconds), adjusted by an age factor of essentially 1.0 at that age, giving a rating of roughly 61 out of 100. The same 21:00 from a 70-year-old male, whose age factor is 0.735, gives an age-adjusted standard closer to 17:26 — pushing the rating up to around 83 out of 100, in "Regional class" territory.
What the rating bands mean
A rating of 100 or above is World class, 90-99 National class, 80-89 Regional class, and 70-79 Local class, with anything below classed as Recreational. Very few runners exceed 80 even at a strong club level, so a rating in the 60-70 range from consistent training is a solid, realistic benchmark for most recreational runners.
Choosing a reference run
A recent 10K or longer run tends to give a more optimistic (faster) 5K prediction than a shorter, harder effort, because Riegel assumes similar relative fitness across distances — pick a training run or race result reasonably close to 5K in duration if you want the most realistic estimate.