VDOT Calculator (Jack Daniels) with Equivalent Race Times

Understanding the VDOT calculator — concept and principle

VDOT is coach Jack Daniels' running fitness score. It is the VO2 max value (in mL/kg/min) that would explain your race performance, so it rolls aerobic capacity and running economy into one number. From one race result you get your VDOT, equivalent race times and approximate training paces.

Dividing the oxygen you used by the share you could sustain reveals the full tank.

How it is calculated

Daniels and Gilbert used two equations, with v = speed in metres per minute and t = race time in minutes:

Oxygen cost of running: VO2 = −4.60 + 0.182258 × v + 0.000104 × v²
Fraction of VO2 max you can sustain for t minutes: %max = 0.8 + 0.1894393 × e^(−0.012778 t) + 0.2989558 × e^(−0.1932605 t)
VDOT = VO2 ÷ %max

Equivalent times are the times that give the same VDOT at other distances. The training paces use vVO2max, the speed whose oxygen cost equals your VDOT: easy runs at about 65–79% of that speed and threshold runs at about 88%.

The principle

The first equation says how much oxygen a typical runner needs at a given speed. The second says how close to maximum you can stay for a race of that duration: about 100% for 10 minutes, about 94% for 25 minutes and about 81% for four hours. Dividing the oxygen you were using by the share of capacity you could sustain gives the capacity itself. Two runners with the same VDOT should race similar times even if their lab VO2 max differs.

Worked example

Result: 5 km in 25:00.

Speed v = 5000 ÷ 25 = 200 m/min.
VO2 = −4.60 + 0.182258 × 200 + 0.000104 × 200² = 36.012.
%max = 0.8 + 0.13764 + 0.00238 = 0.94002.
VDOT = 36.012 ÷ 0.94002 = 38.31.
Solving for the same VDOT gives 51:53 for 10 km, 1:55:04 for the half marathon and 3:57:55 for the marathon.
vVO2max = 210.2 m/min, so easy pace is 6:01 – 7:19 /km and threshold pace 5:24 /km.

Each point is the calculator re-run with only “Hours” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Hours	VDOT
0	38.31
1	7.5
2	2.18
3	-0.11
4	-1.39
5	-2.21
6	-2.76

How to read the result

Higher VDOT means faster racing. Values in the 30s are typical of recreational runners, the 50s of strong club runners, and the high 70s and above of elite men. One extra point means a race time roughly 1.5–2% faster. Most useful are the paces: easy days in the easy range, threshold sessions near 5:24 /km.

Common mistakes

Using a training run instead of a real race effort.
Expecting the marathon time without marathon-specific training.

Keep in mind: VDOT is a model built from trained runners. Heat, hills and your personal endurance profile can make equivalent times wrong by minutes. The paces here approximate Daniels' published tables rather than reproducing them exactly.

Frequently asked questions

Why is the marathon time here faster than the Riegel prediction?

The two models assume different fatigue curves. Here the marathon is 3:57:55 versus 3:59:47 with Riegel; real results for most recreational runners are slower than both.

How often should I update my VDOT?

After each new race. Raise training paces only when a race confirms the gain.

Is VDOT the same as VO2 max?

No. It is an effective VO2 max that also reflects running economy, so an economical runner can have a VDOT above their measured VO2 max.

Sources: Daniels J, Gilbert J. Oxygen Power: Performance Tables for Distance Runners. 1979. · Daniels J. Daniels' Running Formula. Human Kinetics.

Checked 8 Nov 2026. Daniels & Gilbert, Oxygen Power (1979); Daniels’ Running Formula.

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