Training paces Training Paces Calculator (Jack Daniels)

Enter your reference time (5k, 10k, half marathon, marathon or other distance) to automatically get your E / M / T / I / R zones. Paces are based on VDOT percentages popularized by Jack Daniels.

Who is Jack Daniels?

Jack Daniels is an American physiologist and coach born in 1933. Former Olympic medalist in modern pentathlon, he is best known for his work on VDOT, a scientific approach that links oxygen consumption and running performance. His book Daniels' Running Formula is a reference for structuring training plans for runners of all levels.

  • Doctor in exercise physiology, specialist in endurance sports.
  • Coach of numerous NCAA and Olympic athletes since the 1970s.
  • Creator of E / M / T / I / R zones that help balance volume and intensity.

Enter your time

E

Easy endurance

--:-- min/km
—

Easy runs, active recovery.

M

Marathon pace

--:-- min/km
—

Long rhythmic runs.

T

Threshold / tempo

--:-- min/km
—

Controlled effort 20-40 min.

I

Interval

--:-- min/km
—

Intervals near V̇O₂max.

R

Repetition / short speed

--:-- min/km
—

Fast series, technique.

How to read these paces?

  • E (Endurance): 65–78% of your V̇O₂max, easy conversation.
  • M (Marathon): 80–84% of your V̇O₂max, sustainable ~2–3 h.
  • T (Tempo): 88–92%, controlled lactate effort.
  • I (Interval): 95–100%, repetitions 3–5 min.
  • R (Repetition): 105%+ critical speed, neuromuscular work.

These ranges come from Jack Daniels' VDOT tables. Adjust according to your experience, weather and fatigue.

Why use this calculator?

Daniels' paces directly link your race time to your training speeds to structure blocks (endurance, marathon, threshold, interval, repetition). This prevents training too fast or too slow, by basing your training load on an objective indicator: VDOT.

To optimize your training, you can also:

Zone Objective Feeling / RPE
E Aerobic base + recovery Easy, fluid conversation (RPE 3–4)
M Marathon specific Smooth but sustained (RPE 5–6)
T Improve lactate threshold Controlled but demanding (RPE 7)
I VO₂ max Hard breathing (RPE 8–9)
R Speed / running economy Very intense, full recovery (RPE 9–10)