The “magic mile” is a one-mile time trial run at your best sustainable effort. Galloway adds a margin for longer races, giving a conservative pace that most runners can actually hold.
How to use the Magic Mile Calculator
- Magic mile time – minutes
- seconds
- Target race
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Enter your magic mile time and choose the race you are training for.
Inputs explained
| Field | What to enter |
|---|---|
| Magic mile time – minutes | A number |
| seconds | A number |
| Target race | Choose one: 5K, 10K, 10 miles, Half marathon … |
What each result means
- Predicted pace per mile = [p]÷60
- Predicted pace per km = [p]÷1.609344÷60
- Predicted finish time = [p]×[d]÷1609.344
- Average speed = 1609.344÷[p]
Formula
Pace per mile: 5K = mile + 33 s · 10K = mile × 1.15 · 10 mi = mile × 1.175 · Half marathon = mile × 1.2 · Marathon = mile × 1.3
Worked example
Inputs — Magic mile time – minutes: 8; seconds: 0; Target race: Marathon.
Results — Predicted pace per mile = 10:24; Predicted pace per km = 6:28; Predicted finish time = 4:32:41; Average speed = 9.28 km/h.
Key terms
- Magic mile
- One-mile time trial used for pace prediction.
Frequently asked questions
How do I run a magic mile?
Warm up, then run one mile (4 laps of a track) at a hard but controlled effort.
How often should I repeat it?
Every 2–3 weeks to track progress.
Why is the marathon pace so much slower?
Fatigue and fuel limits grow with distance.
Is the prediction conservative?
Yes – it is designed for finishing strong, not racing all-out.