McMillan Running Calculator
Race time equivalents and training paces.
Enter your values
Results update instantly as you type — no submit needed.
Results
- 5K equivalent
- 22:30
- 10K equivalent
- 46:55
- Half marathon
- 1:43:30
- Marathon
- 3:35:48
- Easy pace
- 10:12 /mi
- Tempo pace
- 7:56 /mi
Working
- 1Mile equivalent: 6:46
- 2Marathon pace: 8:14 /mi
- 3Equivalents assume equal training for each distance.
Quick answer
Race equivalency uses Riegel's formula T₂ = T₁ × (D₂ ÷ D₁)^1.06, the same power-law behind McMillan-style running calculators.
T₂ = T₁ × (D₂ ÷ D₁)^1.06
At a glance
| What it does | Race time equivalents and training paces. |
|---|---|
| Category | Fitness |
| Inputs needed | Race distance, Finish time — minutes, Finish time — seconds |
| Main output | 5K equivalent |
| Formula | T₂ = T₁ × (D₂ ÷ D₁)^1.06 |
| Cost | Free — no sign-up, no download |
How to use the McMillan Running Calculator
- 1Pick the distance you raced.
- 2Enter your finish time in minutes and seconds.
- 3Read equivalent times and training paces.
Inputs explained
- Race distance
- Choose one of: 1 mile, 5K, 10K, Half marathon, Marathon.
- Finish time — minutes
- Enter the finish time — minutes you are working with.
- Finish time — seconds
- Enter the finish time — seconds you are working with.
Worked example
Using the values the calculator loads with:
Inputs
- Race distance5K
- Finish time — minutes22
- Finish time — seconds30
Results
- 5K equivalent22:30
- 10K equivalent46:55
- Half marathon1:43:30
- Marathon3:35:48
- Easy pace10:12 /mi
- Tempo pace7:56 /mi
- Mile equivalent: 6:46
- Marathon pace: 8:14 /mi
- Equivalents assume equal training for each distance.
Frequently asked questions
How accurate are race equivalency predictions?
Very good from 5K to half marathon; marathon predictions assume you've done the long-run training to support them.
What is the Riegel exponent?
1.06 — the power that models how pace slows as distance grows. Fatigue-resistant runners are closer to 1.04.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.