Running Race Time Predictor



Use this calculator to predict your time and pace based on a previous race. Enter a race time above, and the calculator will predict your race time. This calculator assumes that you have trained appropriately for the distance

How to predict race times accurately?

The Race Time Predictor Calculator makes use of an equation proposed by Riegel (1981). The equation proposed by Riegel can be accurately used to predict race times from 1mile to Half Marathon, a study conducted in 2016 found that for distances above the Half Marathon it tends to be too optimistic. Read more about Riegel's formula.

What was Riegel's Equation for estimating race times?

T2 = T1 x (D2/D1)^1.06

  • T2 = Goal Race Time
  • T1 = Recent Race Time
  • D2 = Goal Race Distance
  • D1 = Recent Race Distance
  • 1.06 = Riegel's Constant

The effects of Training on calculations

The Race Time Predictor assumes that you have trained adequately for the distance. For example, if you run a 5k in 25min, you can't expect to do a Half Marathon in the indicated time if you haven't trained sufficiently for the distance.

Calculators for runners

Running Mileage Increase Calculator
Running Base Building Calculator. Use this calculator to safely increase your total distance each week. Generate a FREE training plan and download as .xlsx'
View
Running Pace Calculator
How long will it take you to run a specified distance? Use this calculator to find out. Use either Km or Miles.
View
Pete Pfitzinger Lactate Threshold Calculator
Calculate your Lactate Threshold Pace according to the principles that Pete Pfitzinger outlines in his book: "Faster Road Racing"
View
Running Negative Splits Calculator
The split calculator allows you to calculate what your lap (split) times should be for a given distance. You can also calculate negative or positive splits.
View