Jack Daniels Running Calculator
Calculate your VDOT score using the Jack Daniels formula calculator. Get equivalent race predictions and personalized training paces for Easy, Marathon, Threshold, Interval, and Repetition zones.
Calculate Your VDOT
Enter a recent race performance to find your VDOT and training paces
Enter your race distance and time above to calculate your VDOT and training paces.
For best results, use a recent all-out race effort from the past 4-6 weeks.
About the Jack Daniels VDOT Calculator
Learn more about the calculator and its creator
Jonas
I have been a runner for over 10 years and I built this calculator to help runners like you and me with training and racing.
Understanding VDOT and the Jack Daniels Formula
The Jack Daniels VDOT system is one of the most trusted methods for determining training paces and predicting race times in distance running.
Developed by legendary running coach Dr. Jack Daniels and exercise physiologist Jimmy Gilbert, this calculator uses the scientifically validated Daniels-Gilbert formula to translate your race performance into actionable training guidance.
What is VDOT?
VDOT is a pseudo-VO2max value that represents your running fitness. Unlike laboratory VO2max testing, VDOT incorporates both your aerobic capacity and running economy into a single performance index. Two runners with identical lab VO2max values might have different VDOTs if one runs more efficiently.
The Daniels-Gilbert Formula
The VDOT calculation uses a regression equation relating oxygen cost to velocity and sustainable effort over time:
VDOT = (−4.60 + 0.182258 × V + 0.000104 × V²) ÷ (0.8 + 0.1894393 × e−0.012778×T + 0.2989558 × e−0.1932605×T)
Where V = velocity in meters per minute, T = time in minutes, e = Euler's number (2.718...)
The numerator estimates oxygen cost at a given running velocity. The denominator calculates what fraction of your VO2max you can sustain for a given duration—shorter races allow higher percentages.
VDOT Reference Table
Here are sample VDOT values with their corresponding race times:
| VDOT | 5K | 10K | Half Marathon | Marathon |
|---|---|---|---|---|
| 35 | 28:22 | 59:00 | 2:10:30 | 4:32:00 |
| 40 | 24:40 | 51:16 | 1:52:46 | 3:55:00 |
| 45 | 21:51 | 45:16 | 1:39:36 | 3:28:00 |
| 50 | 19:31 | 40:27 | 1:29:04 | 3:07:00 |
| 55 | 17:36 | 36:26 | 1:20:23 | 2:49:00 |
| 60 | 16:00 | 33:06 | 1:13:02 | 2:33:00 |
| 65 | 14:39 | 30:18 | 1:06:48 | 2:20:00 |
| 70 | 13:30 | 27:55 | 1:01:29 | 2:09:00 |
The Five Training Zones
Jack Daniels defines five training intensities, each targeting specific physiological adaptations:
| Zone | Name | % vVO2max | Purpose |
|---|---|---|---|
| E | Easy / Long | 59-74% | Aerobic base, recovery |
| M | Marathon | 75-84% | Race-specific endurance |
| T | Threshold | 83-88% | Lactate threshold improvement |
| I | Interval | 95-100% | VO2max development |
| R | Repetition | 105-115% | Speed and economy |
Example Calculation
Runner's recent race: 5K in 22:00
1. Calculate velocity: 5000m ÷ 22min = 227.3 m/min
2. Apply the formula: VDOT = 44.7
3. Predicted times:
- 10K: ~45:40
- Half Marathon: ~1:40:30
- Marathon: ~3:30:00
4. Training paces (approximate):
- Easy: 5:45-6:30 min/km
- Marathon: 5:00 min/km
- Threshold: 4:35 min/km
- Interval: 4:15 min/km
- Repetition: 3:55 min/km
How to Use Your Results
Once you have your VDOT and training paces:
- Easy runs should make up 70-80% of your weekly mileage
- Tempo runs at Threshold pace improve lactate clearance (20-40 min efforts)
- Interval sessions at I pace develop VO2max (3-5 min repeats)
- Repetition work at R pace builds speed and economy (200-400m repeats)
- Marathon pace runs prepare you specifically for 26.2 miles
Note: VDOT predictions assume equal training for all distances. Your actual race times may vary based on training specificity, course difficulty, weather, and race-day execution. Recalculate your VDOT every 4-8 weeks as your fitness improves.
Learn More About VDOT Training
Explore our detailed guides on using the Jack Daniels system:
- Jack Daniels Running Table - Complete VDOT reference tables
- Jack Daniels Running Chart - Visual guide to training zones
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Frequently Asked Questions
VDOT is a running performance index developed by coach Jack Daniels. While VO2max measures your body's maximum oxygen uptake in a lab, VDOT is a 'pseudo-VO2max' that combines VO2max with running economy. Two runners with the same lab VO2max might have different VDOTs based on their running efficiency.
The Daniels-Gilbert formula is one of the most validated running performance models. It's based on extensive research correlating race performances across distances. For best accuracy, use a recent all-out race effort from the past 4-6 weeks.
Races between 3K and half marathon typically provide the most reliable VDOT estimates. 5K and 10K races are particularly good because they're long enough to measure aerobic capacity but short enough to run at near-maximum effort.
Race predictions assume equal training specificity for all distances. If you train primarily for 5Ks, your marathon prediction may be optimistic. Other factors like course difficulty, weather, pacing strategy, and race-day nutrition also affect actual performance.
E = Easy (recovery and long runs), M = Marathon pace, T = Threshold/Tempo (lactate threshold work), I = Interval (VO2max development), R = Repetition (speed and running economy). Each zone targets specific physiological adaptations.
Recalculate your VDOT every 4-8 weeks or after any race where you set a PR or ran particularly well. Your VDOT should increase as your fitness improves through consistent training.
Yes, but beginners should use conservative pacing and focus on the Easy zone for most training. The calculator works for any fitness level as long as you input an honest race effort. Start with lower-intensity training before attempting interval workouts.
In heat above 60°F (15°C), slow your paces by 1-3% per 10°F (5°C) increase. At altitude, reduce intensity by 3-6% per 1000m (3000ft) of elevation. Focus on effort rather than pace when conditions are challenging.
VDOT directly predicts marathon time. For example, VDOT 40 predicts ~4:08 marathon, VDOT 50 predicts ~3:20, and VDOT 60 predicts ~2:50. Higher VDOT scores indicate better running fitness and faster race times.
Yes! Easy runs should feel genuinely easy - you should be able to hold a full conversation. Many runners train too fast on easy days, which limits recovery and reduces the quality of hard workouts. Trust the Easy pace range for optimal training adaptation.
What is VDOT and how is it different from VO2max?
How accurate is the Daniels-Gilbert formula?
What race distance gives the most accurate VDOT?
Why are my predicted race times different from my actual times?
What do the training zone letters (E, M, T, I, R) mean?
How often should I recalculate my VDOT?
Can beginners use this calculator?
How should I adjust paces for heat or altitude?
What's the relationship between VDOT and marathon time?
Should Easy runs really feel that easy?
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