Marathon Training Pace Calculator

VDOT is derived from the average speed your goal time requires and the percentage of VO2max research suggests a runner can sustain for that race duration. A faster goal time both demands a higher average velocity and shortens how long you'd need to sustain it, and shorter efforts sustain a higher percentage of VO2max -- both effects push Estimated VDOT up, so cutting your goal time by any amount always raises it, never lowers it.

Every training pace -- Easy, Marathon, Tempo, Interval, and Repetition -- is derived from percentages of the same single Estimated VDOT figure, following Daniels' published training-zone ranges (roughly 59-74% of VO2max for Easy up through 105-120% for Repetition). Because they all scale off one shared number, tightening your goal marathon time raises VDOT and proportionally tightens every training pace at once, not just the marathon-effort pace itself.

They're the intensity zones from Jack Daniels' VDOT training system, each targeting a different physiological adaptation: Easy pace builds aerobic base at a comfortable effort, Tempo (or threshold) pace trains lactate clearance at a "comfortably hard" effort, Interval pace targets VO2max itself, and Repetition pace develops speed and running economy at paces faster than race pace, run for short, well-rested efforts.

It's a population-level estimate derived purely from your goal finish time, not a direct physiological measurement -- an actual VO2max test in an exercise-science lab measures your real oxygen uptake under load. Two runners with identical goal times can have different true fitness levels depending on running economy, pacing ability, and race conditions, so treat the training paces here as a well-grounded starting point to adjust based on how workouts actually feel, not an exact prescription.

Less so. Daniels' velocity-to-VO2 regression was built from data on trained distance runners at genuine running paces, and a 7-hour-plus marathon goal works out to roughly an 18-minute mile -- close to a brisk walk or run/walk pace rather than sustained running. At that end of the range the formula is extrapolating well beyond the paces it was calibrated on, so treat Estimated VDOT and every training pace derived from it as increasingly approximate for slower run/walk goal times, and lean more on perceived effort than on the exact numbers.