McMillan Running Calculator
Race time equivalents and training paces.
Enter your values
Choose one of: 1 mile, 5K, 10K, Half marathon, Marathon.
Enter the finish time — minutes you are working with.
Enter the finish time — seconds you are working with.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- 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.
What do I need to enter into the McMillan Running Calculator?
Just 3 values: race distance, finish time — minutes, finish time — seconds. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the McMillan Running Calculator work out the answer?
Race equivalency uses Riegel's formula T₂ = T₁ × (D₂ ÷ D₁)^1.06, the same power-law behind McMillan-style running calculators. It applies the formula T₂ = T₁ × (D₂ ÷ D₁)^1.06 and shows the working so you can check each step by hand.
Is the McMillan Running Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.