VO2 Max from Race Time Calculator (Daniels)
Estimate your VO2 max from a race time using the Daniels formula.
Enter distance and time for 5K, 10K, half, or marathon to get VDOT and equivalent paces.
VO2 Max from Race Time (Daniels Formula)
The Daniels Running Formula uses a single race time to estimate VO2 max-equivalent fitness (called VDOT in his system) and predict times at other distances.
The Daniels formula: Velocity (m/min) = Distance (m) / Time (min) %VO2max = 0.8 + 0.1894393 × e^(-0.012778 × T) + 0.2989558 × e^(-0.1932605 × T) VO2 = -4.6 + 0.182258 × velocity + 0.000104 × velocity² VDOT = VO2 / %VO2max
Where T is time in minutes for the race.
Why VDOT is useful:
- Single fitness number (around 30-85 for most runners)
- Calculate equivalent times at other distances
- Set training paces (easy, tempo, intervals, repetitions)
- Track fitness changes over time
Approximate VDOT-to-fitness mapping:
| VDOT | Fitness Level |
|---|---|
| 30-35 | Beginner runner |
| 35-40 | Recreational, 5K under 30 min |
| 40-45 | Trained, 5K 24-28 min |
| 45-50 | Solid, 5K 21-24 min |
| 50-55 | Strong, 5K 19-21 min |
| 55-60 | Sub-19 5K, sub-3:30 marathon |
| 60-65 | Sub-17 5K, sub-3:00 marathon |
| 65-70 | Sub-16 5K, sub-2:45 marathon |
| 70-75 | Elite local, sub-15 5K |
| 75-85 | World-class, sub-2:10 marathon |
Equivalent times from VDOT 50:
- 5K: 20:00
- 10K: 41:40
- Half: 1:32:00
- Marathon: 3:13:00
Equivalent times from VDOT 60:
- 5K: 17:03
- 10K: 35:22
- Half: 1:18:00
- Marathon: 2:43:00
Why VDOT predictions might miss:
- Recent training mismatch: if you trained for 5K, half marathon time will be optimistic
- Heat / elevation: Daniels assumes ideal conditions; hot races are 2-5% slower
- Course terrain: hilly, technical courses skew predictions
- Fueling: bonking ruins long-distance times (especially marathon)
- Pacing strategy: even-paced races match VDOT prediction; positive splits don’t
Using VDOT for training: Daniels uses VDOT to set training paces:
| Pace | %VDOT |
|---|---|
| Easy / E | 65-79% |
| Marathon / M | 80-87% |
| Threshold / T | 88-92% |
| Interval / I | 95-100% |
| Repetition / R | 105-115% |
This lets you train in the right zones for VO2 max improvement without guesswork.
Lab VO2 max vs. predicted VDOT: Direct lab testing (graded treadmill or cycling) measures actual VO2 max in mL/kg/min. VDOT is race-derived — incorporates running economy, lactate threshold, and aerobic capacity into one number. They correlate well but VDOT is more practical for non-lab settings.