What VDOT actually measures
VDOT, short for V-dot-O₂max, is a single number that captures your current running fitness. Jack Daniels coined it in Daniels' Running Formula as a 'pseudo-VO₂max': it folds your true aerobic capacity together with your running economy, so two runners with the same lab VO₂max but different economy get different, more useful VDOT values.
The number is derived from the Daniels & Gilbert (1979) equations, which describe both the oxygen cost of running at a given velocity and the fraction of VO₂max a runner can sustain for a race of a given duration. Feed in one race result and the model solves for the VDOT that fits it. A higher VDOT means faster training and racing paces across the board.
The five training paces
VDOT defines five intensities, each a band of VO₂max. Easy/Long runs sit at 59–74% VO₂max and build aerobic base, capillary density and fat metabolism, most weekly volume lives here. Marathon pace is 75–84%, training marathon-specific endurance and economy. Threshold is 83–88% VO₂max, the comfortably-hard tempo you could race for about an hour.
Interval pace is 95–100% VO₂max, run as 3–5-minute hard reps to develop maximal aerobic power. Repetition pace is the fastest, at 105–120% VO₂max, run as short fast reps with full recovery to sharpen speed, economy and running power. Training at the right pace for each purpose is the whole point of the system, too fast on easy days and too slow on hard days both blunt the adaptation.
One race, every pace
The strength of VDOT is that a single all-out race result yields your entire pace prescription. Once the model has your VDOT, it inverts the velocity equation at each intensity to produce Easy, Marathon, Threshold, Interval and Repetition paces directly, no separate test for each zone.
Use a recent, genuinely all-out race or time trial of at least 5 km. Shorter efforts are skewed by anaerobic contribution and pacing, so 5 km, 10 km or a half marathon give the most stable VDOT. The unit toggle switches every pace between minutes per kilometre and minutes per mile.
Re-testing and limits
VDOT is a snapshot. As you get fitter, re-race and the number, along with all five paces, moves with you; many runners re-test every 4–8 weeks during a focused block. A VDOT from a poorly-paced, hilly, hot or fatigued race will read low and set your paces too easy.
The equations were fitted to well-trained distance runners, so VDOT is most accurate in that population and for events between roughly 1500 m and the marathon. For very short sprints or ultra distances it loses precision, and like any model it assumes you raced honestly to exhaustion.
How to run a VDOT time trial
VDOT needs one honest, all-out result. A 5 km on a track or flat course, run rested, gives a clean number you can plug straight in.
- 1
Warm up thoroughly
10–15 minutes of easy jogging, then a few strides and short pickups to get race-ready.
- 2
Pick a flat, accurate course
Use a 400 m track or a flat, measured road loop, avoid hills, sharp turns, wind and heat, which all distort the result.
- 3
Run an all-out 5 km
Race the full distance at the hardest pace you can hold evenly to the finish. Don't start too fast; aim to finish nearly empty.
- 4
Enter the time
Select 5 km and type your finish time. The calculator returns your VDOT and all five training paces.
Worked example
A runner races 5 km in 20:00 (4:00 /km):
| Race input | 5 km in 20:00 |
| VDOT | ≈ 49.8 |
| Easy pace | 4:54–5:53 /km |
| Threshold pace | 4:16–4:28 /km |
| Interval pace | 3:51–4:01 /km |
Every pace is derived from the single VDOT of 49.8; race faster and they all shift together.
Frequently asked questions
What is a good VDOT?
VDOT scales with fitness: a recreational runner often sits around 35–45, a competitive club runner 50–60, and elite distance runners exceed 70–85. A VDOT of 50 corresponds to roughly a 19:57 5 km. 'Good' is relative, the useful comparison is your own VDOT trend over a training block.
VDOT vs pace zones, what's the difference?
VDOT is the single fitness number; pace zones are what it produces. The model takes your VDOT and outputs five training paces, Easy, Marathon, Threshold, Interval and Repetition, each tied to a band of VO₂max. So VDOT is the input and your five pace zones are the output of the same calculation.
How do I improve my VDOT?
Train consistently across all five paces, but spend most volume on easy aerobic running (59–74% VO₂max) with regular threshold and interval work. As fitness rises you race faster, and re-running an all-out 5 km or 10 km every 4–8 weeks updates your VDOT and all derived paces accordingly.
What's the difference between Threshold and Interval pace?
Threshold pace sits at 83–88% VO₂max, a comfortably-hard tempo you could race for about an hour, used to lift your lactate threshold. Interval pace is harder, at 95–100% VO₂max, run as 3–5-minute reps to develop maximal aerobic power. Threshold is sustained and steady; Interval is shorter and genuinely hard.
Which race distance should I enter?
Use a recent, all-out race of at least 5 km. Distances of 5 km, 10 km or a half marathon give the most stable VDOT because they are paced aerobically. Very short efforts under 1500 m carry a large anaerobic component and tend to over-estimate your VDOT and training paces.
Is VDOT the same as VO₂max?
Not quite. Lab VO₂max measures oxygen uptake only, while VDOT folds in running economy, so it reflects performance rather than physiology alone. Two runners with identical VO₂max can have different VDOTs if one runs more economically. That is why VDOT predicts race pace better than a raw VO₂max number does.
Sources
- Jack Daniels, Daniels' Running Formula (3rd ed.). VDOT tables and the five training-intensity paces (E, M, T, I, R).
- Daniels & Gilbert (1979). “Oxygen Power: Performance Tables for Distance Runners.” The %VO₂max-vs-duration and VO₂-vs-velocity equations behind VDOT.