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VDOT Calculator (Daniels Running)

VDOT is Jack Daniels' fitness index — a single number that combines your race performance with the physiology of running economy and sustainable percentage of VO2 max. Given one accurate race result, VDOT predicts equivalent finish times at other standard distances and prescribes five intensity bands (Easy, Marathon, Threshold, Interval, Repetition) for structured training. The model is published in Daniels' Running Formula. Estimates are for educational and training-planning purposes only.

Reviewed by GetHealthyCalculators Editorial Team · Updated May 14, 2026

Quick Answer

Enter one race time. VDOT estimates the VO2-max-equivalent intensity you sustained, then projects equivalent times at every standard distance and prescribes paces for Easy, Marathon, Threshold, Interval, and Repetition workouts. A 25-minute 5K is roughly VDOT 41.

These results are estimates based on general formulas and are not a substitute for professional medical advice. Consult a healthcare provider before making health decisions.

Finishing time

How the Formula Works

  1. Convert your race distance and time to velocity in meters per minute.

    v = distance(m) / time(min)

  2. Compute the oxygen cost of running at that velocity (Daniels 1979).

    VO2 = -4.60 + 0.182258·v + 0.000104·v²

  3. Compute the percent of VO2 max sustainable for the race duration.

    %max = 0.8 + 0.1894·exp(-0.0128·t) + 0.2990·exp(-0.1933·t)

  4. Solve for VDOT.

    VDOT = VO2 / %max

  5. Invert the same equation at every other distance to project equivalent times.

    For each distance: find v such that VO2(v) = VDOT × %max(time at that distance)

Methodology & Sources

Reviewed and updated May 14, 2026 · Prepared by GetHealthyCalculators Editorial Team

The VDOT equations come from Daniels' Running Formula (3rd ed., Human Kinetics, 2014) and the original Daniels & Gilbert "Oxygen Power" tables (1979). Equivalent times are computed by inverting the same cost-of-running and percent-max-sustainable relationship at each target distance, using a 30-iteration fixed-point solve. Training pace bands use the published Daniels intensity percentages: Easy 59-74%, Marathon 75-84%, Threshold 83-88%, Interval 95-100%, Repetition ~100-106% of VDOT.

References

  • Daniels J. Daniels' Running Formula, 3rd ed. (2014) · Human Kinetics
  • Daniels J, Gilbert J. Oxygen Power: Performance Tables for Distance Runners (1979) · Tafnews Press
  • Joyner MJ, Coyle EF. Endurance exercise performance: the physiology of champions (2008) · The Journal of Physiology

Limitations

  • VDOT assumes the input race was paced near maximum sustainable effort. Tactical races, group runs, and training runs will produce a lower VDOT than your true fitness.
  • Equivalent times at much longer distances than your input race assume training specificity. A fast 5K does not guarantee an equivalent marathon time without long-run training.
  • Hot, humid, or hilly courses depress race performance and bias VDOT low.
  • The model treats running economy as a single regression. Real economy varies 15-20% between runners, which shifts VDOT estimates accordingly.
  • Training pace bands are starting points, not prescriptions. Adjust for terrain, fatigue, and goal specificity.
  • VDOT is sensitive to small input errors. A 30-second error on a 5K time shifts VDOT by roughly 1 point.

Frequently Asked Questions

What does the VDOT number actually mean?
It is the VO2-max-equivalent intensity (in ml O2 per kg per minute) that you can sustain at race effort, accounting for both your running economy and the fraction of VO2 max sustainable for that race duration. It is not the same as your laboratory-measured VO2 max — most runners have a lab VO2 max 5-15% higher than their VDOT.
Why are the equivalent times slower than my actual race times?
They should be close if your training is balanced across distances. If your 5K time is much faster than your VDOT-equivalent marathon, you probably need more endurance work. If your marathon is much faster than your equivalent 5K, you need more speed work. The mismatch is information.
How is VDOT different from the Riegel formula?
Riegel uses a single power-law exponent (1.06) to scale race times across distances. VDOT uses an explicit physiology model with VO2 cost and sustainable percentage curves. VDOT is generally more accurate at the extremes (very short and very long distances) and provides training paces, which Riegel does not.
What are E / M / T / I / R paces for?
Easy (E) builds aerobic base and recovery. Marathon (M) is goal marathon pace work. Threshold (T) is tempo running at one-hour race pace — the most efficient pace for raising lactate threshold. Interval (I) is 3-5 minute reps at VO2 max. Repetition (R) is short fast reps for economy and speed. Most plans run 70-80% Easy, with the harder intensities sprinkled in.
How fast does VDOT improve?
A 1-2 point gain over a focused 8-12 week training block is realistic for an experienced runner. Beginners can gain 3-5 points in their first year of structured training. Gains slow as VDOT increases — moving from VDOT 60 to VDOT 62 takes far more work than from 40 to 42.
Should I race at my predicted equivalent time?
It is a planning anchor, not a guarantee. Use it as your A-goal target if your training has been specific to the race distance. For distances you have not trained for, predicted times tend to be too optimistic.
Is VDOT useful for trail or ultra running?
The model breaks down on technical terrain, big climbs, and ultra distances where pacing is dominated by fueling and fatigue rather than aerobic ceiling. Use VDOT as a road-running reference and adjust pace expectations for terrain.

Cross-check your training intensity with heart rate zones

Heart Rate Zone Calculator

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