What does VDOT stand for?

VDOT is a pseudo-acronym for "VO₂max" written with a dot above the V (the dot indicates a rate). It represents the oxygen cost equivalent of your race performance — not a direct VO₂max measurement, but a number that captures both your VO₂max and your running economy.

Should I use a 5K or marathon time?

Use whichever distance you've raced most recently and most maximally. Shorter races (5K/10K) reflect VO₂max more directly; marathon times reflect lactate threshold and fueling. If you're training for a marathon, the marathon time is more predictive of your fatigue-resistance.

Why are my training paces faster than other calculators say?

Some online calculators use the simpler Riegel formula or older lookup tables. This page implements Daniels' polynomial regressions directly from Daniels' Running Formula 3rd ed., which match the official Daniels VDOT tables to ±1 second per kilometer.

How do the five Daniels paces work?

Easy (E) builds aerobic capacity at 70% VO₂max. Marathon (M) is your goal marathon pace. Threshold (T) is "comfortably hard" tempo at lactate threshold. Interval (I) is 3–5 min reps at VO₂max pace. Repetition (R) is 200–600 m reps at neuromuscular pace, faster than VO₂max. Each targets a distinct physiological adaptation.

How often should I recompute VDOT?

After every legitimate race or hard time trial. AthleteOS auto-updates VDOT continuously from race results and tempo workouts, so your training paces evolve with your fitness without you having to retest.

Daniels VDOT Pace Calculator

How the formula works

Jack Daniels' VDOT system converts a race time into a single number that represents the oxygen cost of your race performance. It does this in two steps. First, the velocity of the race (in meters per minute) is mapped to an oxygen cost using a polynomial regression Daniels fit against laboratory gas-exchange data:

VO₂(v) = −4.6 + 0.182258·v + 0.000104·v²

Second, the percentage of VO₂max you can sustain for a given race duration is modelled with a double-exponential curve:

%VO₂max(t) = 0.8 + 0.1894393·e^{−0.012778·t} + 0.2989558·e^{−0.1932605·t}

Divide the first by the second and you get VDOT — the oxygen cost equivalent. Two athletes who run the same 5K time have the same VDOT, even if their actual VO₂max numbers differ (one has higher economy, the other higher VO₂max — they cancel out).

The five Daniels training paces

E (Easy) — 70% VO₂max. Builds capillary density, mitochondrial enzymes, fat-oxidation. The bulk of your weekly volume.
M (Marathon) — 80% VO₂max. Goal marathon-pace fatigue resistance.
T (Threshold) — 88% VO₂max. Lactate-clearance training. 20–60 min total at this pace.
I (Interval) — 98% VO₂max. 3–5 min reps with equal recovery. Drives VO₂max gains.
R (Repetition) — 105% VO₂max+. 200–600 m reps with full recovery. Trains running economy and neuromuscular speed.

Each pace targets a distinct adaptation. Daniels' rule of thumb: never substitute a faster pace for a slower one — running easy days at marathon pace doesn't make you fitter, it just makes you more tired.

What it's good for

Setting precise training paces. A VDOT of 50 maps directly to T pace 4:04/km, I pace 3:42/km, etc. — no guessing.
Equating performances across distances. A VDOT-50 5K time (19:57) is "equivalent" to a VDOT-50 marathon time (3:14:06).
Tracking fitness without a fresh race. A solid threshold workout that hits the prescribed T pace at the prescribed RPE is evidence your VDOT is intact.

Limitations

The %VO₂max curve assumes maximal effort. Race times that weren't all-out understate VDOT.
Marathon performance depends on more than VO₂max. Fueling, glycogen depletion, and heat tolerance all bend the long-distance VDOT estimate.
Single-distance bias. An untrained marathoner's 5K time will overestimate marathon VDOT; an untrained 5K runner's marathon time will underestimate 5K VDOT. Use the distance closest to your event.
It's a runner-specific model. Don't apply VDOT paces to cycling or rowing — those sports have different economy curves.

VDOT in your AthleteOS dashboard

AthleteOS auto-computes VDOT from every race and time-trial workout, blends it with wearable VO₂max from Garmin or Apple Watch, and prescribes E / M / T / I / R paces in your workouts automatically. When VDOT shifts by 1+ point, your future training paces update instantly — no manual recomputation. Generate your free AI plan and your run sessions will be prescribed with Daniels paces from your live VDOT.

Citation

Daniels J (2013). Daniels' Running Formula, 3rd ed. Human Kinetics. ISBN 978-1450431835. The polynomial regressions used here appear in Appendix A of the 3rd edition and in Daniels & Gilbert's original 1979 monograph Oxygen Power: Performance Tables for Distance Runners.