What is a VDOT score?

VDOT is a single fitness number coined by coach Jack Daniels. It estimates the VO2max-equivalent that, given typical running economy, would produce a given race time. It anchors every training pace and lets one race result predict times at every other distance.

Which race distance gives the most accurate VDOT?

Daniels recommends a 5K to 10K race for most runners. Shorter than 1500m and the result depends heavily on anaerobic capacity. Longer than the half marathon and it depends heavily on fuelling, heat, and pacing discipline, which can drag VDOT down even for fit runners.

Is the VDOT calculator accurate?

It uses Daniels and Gilbert's published 1979 formulas, which are the basis of Daniels' Running Formula. Values match Daniels' tables within roughly one to two VDOT points across the 30 to 80 range. The calculator is a hypothesis, not a verdict. Real-world training feedback is what tunes it.

How do I use my VDOT training paces?

Spend roughly 80 percent of weekly volume at Easy pace. Cap Threshold work at about 10 percent of weekly volume, Interval work at about 8 percent, and Repetition work at about 5 percent. These dosing caps from Daniels matter more than the exact pace numbers.

How often should I recalculate my VDOT?

Recalculate after any honest race result. Mid-block, you do not need to chase a new VDOT every week. A four to six week reassessment cadence is typical. Smart Runner does this automatically when you log a faster race.

Does VDOT account for hills, heat, or altitude?

No. VDOT assumes flat, dry, sea-level race conditions. Adjust your input by mental subtracting roughly 1 to 2 percent of finish time for every notable adverse condition before computing, or trust the field result and override VDOT downward if paces feel wrong.

VDOT Calculator: Jack Daniels Pace Zones & Race Predictor

What this calculator does, in one line

It takes a race result, converts it into a single fitness score (VDOT), and from that score derives every training pace you need and a predicted time at every common race distance. The math is Jack Daniels and Jimmy Gilbert's, published in 1979 and refined in Daniels' Running Formula, 4th edition (Human Kinetics, 2021).

The science, briefly

Raw VO2max is a poor predictor of running performance because two runners with identical lab numbers can run very different times for a 5K. Running economy, the oxygen cost of moving at a given pace, varies. Daniels and Gilbert proposed a workaround: instead of measuring VO2max directly, derive a number that would, given typical economy, produce the race time observed. That number is VDOT, short for "VO2max-dot," the dot being the calculus shorthand for rate-of.

Two equations carry the whole system. The first describes the oxygen cost of running at a given velocity:

VO₂ = −4.60 + 0.182258 · v + 0.000104 · v²

Where v is velocity in meters per minute and VO₂ is the steady-state oxygen demand in ml·kg⁻¹·min⁻¹. The second describes what fraction of maximum aerobic capacity a runner can hold for a given race duration:

% VO₂max = 0.8 + 0.1894393 · e^{−0.012778 · t} + 0.2989558 · e^{−0.1932605 · t}

Where t is race duration in minutes. The curve is asymptotic: at maximal short efforts you operate above 100% of VO2max for a brief period through anaerobic contribution; over hours, the sustainable fraction drops toward ~80%. VDOT is then simply VO₂ / %VO₂max for your race.

To get training paces, the system is inverted. For any target intensity (a fraction of VDOT), solve the velocity equation for v, then convert to pace per kilometer or mile. To get race time predictions at another distance, find the time at which the oxygen cost of running that distance equals VDOT times the %VO₂max sustainable for that duration. This calculator solves both numerically.

The five paces and what each one trains

Daniels defined five training intensities. Each one targets a specific adaptation, and stacking too much volume in any of them past the dosing caps below is the single most common cause of stalled progress and overuse injury in amateur marathon programs.

Easy (E): ~65-78% of VO2max. The base of the pyramid. Builds capillary density, mitochondrial volume, and structural resilience in tendons and bone. The bulk of weekly volume - 70 to 85 percent - should sit here. Going too hard on easy days is the most common training error in self-coached runners (Seiler's polarized-training research, repeatedly confirmed in trained populations).
Marathon (M): ~82-88% of VO2max. The pace you would race a marathon at right now. Used in long-run pickups, marathon-specific blocks, and tune-up sessions.
Threshold (T): ~86-90% of VO2max. "Comfortably hard." Roughly the pace you could sustain flat-out for 60 minutes. Improves lactate clearance and shifts your lactate threshold upward. Cap: ≤10% of weekly volume.
Interval (I): ~95-100% of VO2max, roughly 3K to 5K race pace. Pushes the VO2max ceiling itself upward. Done as reps of 3 to 5 minutes with equal-or-shorter recoveries. Cap: ≤8% of weekly volume, or ~10 km of work per session, whichever is less.
Repetition (R): Faster than 1500m race pace, run as short reps with full recovery. Trains neuromuscular coordination and running economy. Cap: ≤5% of weekly volume.

Which race should you enter?

Any one will work mathematically. They will not all give the same VDOT.

For most trained runners, a 5K to 10K race is the sweet spot. Short enough that pacing errors do not destroy the result, long enough that aerobic capacity dominates over anaerobic contribution.

Distances shorter than 1500m are dominated by anaerobic capacity and speed mechanics, neither of which scale cleanly to marathon prediction.

Distances longer than the half marathon are dominated by fuelling, heat tolerance, and pacing discipline. A bad marathon can underestimate your true VDOT by several points without any change in fitness. If you only have a marathon time and you bonked, expect this calculator to underrate you.

Why the calculator's number might not match Daniels' printed table

Daniels' tables are tuned with small adjustments on top of the analytical formulas. The published curves we use will produce VDOT values within roughly one to two points of the printed table across the 30-80 range. That is well within the noise of one race result. If you want to anchor to the book table exactly, look up the closest VDOT for your race time in Daniels' Running Formula 4th edition, and use that.

Honest caveats

VDOT is a hypothesis, not a verdict. The number is genuinely useful for setting paces, but it does not know:

Whether your input race was run with heavy legs or fresh legs.
Whether your easy days actually feel easy this week.
How heat, hills, or altitude affected the input result.
Whether you have unusual running economy (taller and heavier runners are often "punished" by VDOT relative to their true fitness; very efficient small runners are sometimes flattered).
Whether you are mid-block in heavy strength training, which can suppress race-day output.

The professional habit is to recalculate after each honest race, and to override the number by a point or two if every threshold rep is too hard or every easy run is too easy. Smart Runner exposes this override explicitly in Settings. The number is a starting hypothesis. Your body is the test.

How Smart Runner uses VDOT

Smart Runner computes your VDOT from a race result during onboarding, then uses it to set the pace target for every workout in your plan. When you complete a faster race, VDOT recomputes and every future workout retunes. You can override it manually in Settings if the paces feel off.

On top of VDOT, the plan layers progression rules from Pfitzinger (mileage and long-run progression) and Canova (specific endurance and marathon-pace work in the final block), and tracks weekly training load with ATL, CTL, and TSB so that the plan stays adaptive rather than rigid.

Frequently asked

What is a "good" VDOT?

It depends entirely on your context. Trained recreational male runners often sit in the 45-55 range; trained recreational female runners in the 42-52 range. Elite male marathoners are around 80-85; elite female marathoners around 75-80. A VDOT of 35 is a healthy beginner. The number is only meaningful versus your own previous VDOT.

Can I use a treadmill or solo time-trial result?

You can, but expect drift. Treadmill belts vary and most runners cannot pace a solo time-trial to true race effort. Use a real race when one is available.

Should I race a 5K every six weeks to retest?

No. Racing fully recovered is taxing and the adaptation curve does not move that fast. A four to eight week cadence is plenty. Better: use a parkrun or a B-race as a hard time-trial inside your build, rather than peaking specifically to retest VDOT.

How do age and sex affect VDOT?

They do not affect the calculator itself - it converts time to VDOT without any age or sex adjustment. They do affect what VDOT you should expect to be capable of. Daniels publishes age-graded tables separately for context.

Why are my Easy paces showing a range?

Daniels' Easy zone spans roughly 65-78% of VO2max for good reason. The lower end is for recovery days, the upper end for steady aerobic days where conversation is still possible. Both are "easy" - pick the end that matches the purpose of the day.

References

Daniels, J. & Gilbert, J. (1979). Oxygen Power: Performance Tables for Distance Runners. Tafnews Press. The original VDOT formulation.
Daniels, J. (2021). Daniels' Running Formula (4th ed.). Human Kinetics. The canonical modern reference for VDOT, the five training paces, and dosing caps.
Seiler, S. (2010). "What is best practice for training intensity and duration distribution in endurance athletes?" International Journal of Sports Physiology and Performance, 5(3), 276-291. Evidence for the ~80/20 polarized distribution at Easy vs. high intensity.
Pfitzinger, P. & Douglas, S. (2019). Advanced Marathoning (3rd ed.). Human Kinetics. Mileage progression and long-run logic layered on top of VDOT-style pacing.

VDOT Calculator

Training paces

Equivalent race times