running training plan

Race time prediction for runners

There can never be a completely accurate means of predicting race performances, perhaps if there was many of us wouldn't bother to run races.
However, performance calculators can be of real benefit and interest to runners who want to compare and predict their race times across various distances, e.g. predicting marathon time from 10k time.

The calculator below is based on the work of Peter Riegel, who, many years ago, discovered that race performances and times could be surprisingly accurately predicted according to a fatigue factor. This fatigue factor is simply a constant multiple applied from one (known) performance to the other (predicted) performance. Most race time predictors found online use the same formula.

We have found that using the typical fatigue factor can produce slightly ambitious estimates especially as the distances increase and have made minor adjustments to improve accuracy for most runners.

Race time calculator

Known race distance (e.g. marathon = 42.195k)

Time for that race (in h:mins:secs)
::

Predict time for

Your race time prediction
: :

Peter Riegel's original article makes very interesting reading for anyone involved in endurance sport: Athletics Records and Human Endurance

Links to Running Tools, Calculators and Pace Conversion sheets

Training Paces calculator
Body Mass Index calculator
Predicting race times
VO2MAX calculation
Pace calculator
Pace and time conversion chart: mph kph minutes/mile minutes/km
Interval session pace conversion sheet: 5k, 10k, half marathon, marathon

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