What is the Magic Mile?

The Magic Mile is a race-prediction method developed by Olympian Jeff Galloway. Run a single hard mile, then apply Galloway pace adjustments to predict 5K, 10K, half-marathon, and marathon times. It is quick, requires no calculator, and works for runners of all levels.

How do the Galloway adjustments work?

From your mile time, add: +33 seconds per mile for 5K pace, +60 seconds for 10K pace, +80 seconds for half-marathon pace, and +180 seconds (3 minutes) for marathon pace. Multiply by the race distance for total time.

How accurate are the predictions?

For 5K and 10K predictions, accuracy is generally within 1-3% for trained runners with appropriate base mileage. Half-marathon and marathon predictions are less accurate (5-10% error) because they assume sufficient long-run training, which the mile time alone cannot verify.

How should I run the Magic Mile?

Warm up for 10-15 minutes including a few short strides. Run a single mile as hard as you can sustain — you should finish near maximum effort but able to keep going briefly. Cool down with easy jogging. Use a flat, measured course (track is ideal) for best results.

How does Magic Mile compare to Riegel or VDOT?

Riegel uses a power-law equation calibrated empirically; VDOT uses a more sophisticated physiological model. Magic Mile is the simplest and works well for short distances. For marathon predictions, VDOT or Riegel from a longer race will generally be more accurate.

Magic Mile Race Predictor

Jeff Galloway's pace-trial method: turn one all-out mile into 5K, 10K, half marathon, and marathon predictions.

Calculator

Why a Mile?

A mile is short enough to give a maximal effort, long enough to involve aerobic capacity, and standardized enough to track over time. Running it monthly produces a clean fitness benchmark that doubles as a race predictor.

When the Predictions Break Down

Without specific endurance training, marathon predictions overestimate. A 6:00 mile in someone who has never run more than 8 miles in a session does not translate to a 4:18 marathon — the long-run training simply is not there. Use the prediction as a ceiling, not a guaranteed time.

Formula

5K pace = mile time + 33 sec/mi

10K pace = mile time + 60 sec/mi

Half marathon pace = mile time + 80 sec/mi

Marathon pace = mile time + 180 sec/mi

Galloway Pace Adjustments

RacePace Add per Mile

5K+33 seconds

10K+60 seconds

Half Marathon+80 seconds

Marathon+3 minutes

Medical Disclaimer

Predictions assume appropriate training for the target distance. A great mile time without long-run endurance will not translate into the predicted marathon time.

Magic Mile Race Predictor

Why a Mile?

When the Predictions Break Down

Formula

Galloway Pace Adjustments

Medical Disclaimer

Frequently Asked Questions

Related Calculators

Track Your Magic Mile Over Time