VO2max · VDOT Calculator
All you need is one recent, genuinely hard effort.
The Jack Daniels formula estimates your VO2max and the five E/M/T/I/R training-pace zones.
Jack Daniels 5-zone training paces E / M / T / I / R
| Zone | Pace / km | Speed km/h | Intensity | Purpose |
|---|---|---|---|---|
| E (Easy) | — | — | 59~74% VO2max | Recovery · base fitness |
| M (Marathon) | — | — | 75~84% VO2max | Full-marathon race pace |
| T (Threshold) | — | — | 83~88% VO2max | Lactate threshold — tempo runs |
| I (Interval) | — | — | 95~100% VO2max | Boost VO2max — 3–5 min intervals |
| R (Repetition) | — | — | 105~120% VO2max | Speed · running economy |
Predicted race times Based on the VDOT table
What is VDOT and how is it calculated?
VDOT is a runner-fitness index created in 1979 by Dr. Jack Daniels (coach and exercise physiologist). It is similar to VO2max but also reflects "how well you actually use that oxygen in a race." At the same VO2max, a more efficient runner has a higher VDOT.
Steps (Jack Daniels' original formula)
- Speed v = distance (m) ÷ time (min) → m/min
VO2 = -4.60 + 0.182258v + 0.000104v²(oxygen demand at this pace)%VO2max = 0.8 + 0.1894393·e^(-0.012778t) + 0.2989558·e^(-0.1932605t)(t = time in min; the longer it is, the less of 100% you can use)VDOT = VO2 ÷ %VO2max
5-zone training paces — the standard ratios from Daniels' Running Formula
- E (Easy): 59~74% — 60–150 min, develops capillaries and mitochondria
- M (Marathon): 75~84% — marathon pace, 40–110 min
- T (Threshold): 83~88% — 20–40 min or 1-mile repeats
- I (Interval): 95~100% — 3–5 min, directly stimulates VO2max
- R (Repetition): 105~120% — 200–600 m, speed and form
VO2max conversion — VDOT effectively operates in the same unit range as VO2max (mL/kg/min). This calculator uses the standard conversion VO2max ≈ VDOT × 1.025 (assuming average runner efficiency).
Raising your VDOT is faster together than alone
"80% easy, 20% hard each week" is Jack Daniels' golden rule. Build a crew of runners in the same VDOT range and matching paces makes managing intensity far more natural. Re-measure in six weeks.
