VDOT Calculator

VDOT is a single running fitness number from Jack Daniels and Jimmy Gilbert. It estimates the oxygen cost of your race pace divided by the fraction of VO2max you can sustain for that race duration, giving a VO2max-like value adjusted for running economy. A higher VDOT means faster equivalent race times and quicker training paces. Typical recreational runners land between 30 and 55, while elite marathoners exceed 75.

This tool uses the Daniels-Gilbert equations. First it finds your race velocity in meters per minute, then the oxygen cost VO2 = -4.60 + 0.182258 times velocity + 0.000104 times velocity squared. It divides that by the sustainable fraction %max = 0.8 + 0.1894393 times e to the power (-0.012778 times minutes) + 0.2989558 times e to the power (-0.1932605 times minutes). VDOT is VO2 divided by %max.

They are Daniels' five training zones, set as fractions of VO2max. Easy (about 70%) builds aerobic base, Marathon pace matches your marathon-equivalent race effort, Threshold (about 88%) is comfortably hard tempo work, Interval (about 100% of VO2max) develops your top aerobic power, and Repetition (about 106%) is fast short reps for speed and economy. Each pace is shown per mile, per kilometer, and per 400 meters.

Equivalent times assume equal fitness, terrain, and weather across distances, plus solid pacing and fueling. Predictions are most reliable within roughly half to double the distance you actually raced. A marathon time predicted from a 5K usually reads optimistic, because the model does not account for glycogen depletion or late-race fade over 26.2 miles.

Use a recent, all-out effort over a distance close to your training focus. A race in the last few weeks reflects your current fitness better than an old personal best. For everyday training-pace guidance a 5K or 10K works well, while marathon and half marathon goals are better anchored by a longer recent race.

No. VO2max is a lab measurement of maximal oxygen uptake, while VDOT is a performance-based estimate derived from a race result. VDOT folds in running economy and the duration you can hold a high effort, so two runners with the same lab VO2max can have different VDOT scores. Use VDOT for setting paces, not as a clinical fitness measurement.