What is VDOT?
VDOT is a score published by Jack Daniels and Jimmy Gilbert in Oxygen Power in 1979. It describes how much oxygen you use per minute and kilogram of body weight during a race, converted to a comparable scale. A higher VDOT score means a higher race performance, independent of the distance raced.
The value is not measured directly but derived from a race time. It is therefore not a lab measurement of true VO2max, but a performance score used to derive training paces.
How the training paces are calculated
From the VDOT value, the calculator derives five training zones, each as a share of the VO2max used: E at 59 to 74 percent, M as the computed marathon race pace, T at 88 percent, I at 97.5 percent and R at 107.5 percent. These percentages follow the tables in Daniels, Daniels' Running Formula (Human Kinetics). Each percentage converts through the VDOT model into a pace per kilometre, which the calculator also shows per 400 m (for I and R) and per mile.
The five training zones
- E, easy: the bulk of weekly mileage, for aerobic base and recovery.
- M, marathon pace: race pace, usually practised in segments of a long run.
- T, threshold: comfortably hard runs or cruise intervals totalling 20 to 40 minutes.
- I, interval: intervals close to VO2max, typically 3 to 5 minutes of effort with equal jog recovery.
- R, repetition: short, fast reps over 200 to 400 m with long recovery, for running economy and speed.
For the target race distance itself, see the race time predictor; for race-day pacing with splits, see the split calculator.
Example and limits
A 5k in 19:57 gives a VDOT of 50. For this value, threshold pace is 4:15 min/km and interval pace 3:55 min/km. The marathon race equivalent is about 3:10:40.
VDOT reflects an average fitness level and does not account for individual strengths such as raw speed or endurance over very long distances. The training paces are guidelines, not a substitute for lab testing.
Frequently asked questions
What does VDOT 50 mean?
VDOT 50 corresponds to roughly a 5k in 19:57. At this value the calculator gives a threshold pace of 4:15 min/km and an interval pace of 3:55 min/km.
Which zone do I train most often?
Most of your weekly mileage is run in the E zone, easy effort. T, I and R sessions add targeted stimulus but make up only a small share of weekly distance.
Why are I and R also shown per 400 m?
Interval and repetition runs are usually trained on the track in fixed segments like 400 m. The 400 m time lets you check pace directly with a watch or lap counter.
Does the VDOT value change with distance?
Ideally not: the same fitness should give the same VDOT across distances. In practice values vary slightly depending on whether a runner is stronger over short or long distances.
How often should I recalculate the value?
After every meaningful race or time trial, roughly every 6 to 8 weeks during training. This keeps training paces aligned with your current fitness.