Jeff Galloway's Magic Mile Race Prediction Formulas

Jeff Galloway

(for the 5K, 10k, Half Marathon and Marathon distances, based upon a one mile time trial)


Why the Magic Mile
After having worked with over 170,000 runners over 30 years, I've compiled hundreds of performances and have established a prediction formula based upon a one mile time trial. In other words, every 2 weeks or so, you can run a measured mile (at a good, hard pace for you) and use the time to predict what you could run at longer distances.

This assumes that
* You do the training needed for the distance and time goal (See my books Running Year Round Plan and Galloway Training Programs)
* The temperature on the race day of your race is 60F or cooler
* You pace yourself correctly and take the walk breaks necessary for your goal (see the same two books for details)

Take your one mile time and adjust as follows:
add 33 seconds for your pace for a 5K
multiply by 1.15 for 10K pace
multiply by 1.2 for half marathon pace
multiply by 1.3 for marathon pace

Here's how to do the one mile time trial:

1. warm up with a slow one mile run
2. do a few acceleration-gliders (See my books Running Year Round Plan and Galloway Training Programs)
3. pace yourself as even as possible on each quarter mile
4. run about as hard as you could run for one mile--but no puking! (finish feeling that you couldn't have run more than a football field at the same pace)
5. keep walking after the time trial for 5 minutes, and jog a slow 1-6 miles, as needed for the mileage for that day

Predicting race performance:

Take your last 4 one mile time trials
Eliminate the slowest
Average the other three
Use the prediction formula for your race
Adjust for heat and humidity: slow down by 30 sec a mile for every 5 degree temperature increase above 60F


Click here for the pace calculator (and entire article)