Daniels Running Formula Calculator

How the Daniels Running Formula score works

Your score comes from one race. The calculator works out how much oxygen it costs to run at your race speed, then divides that by the share of your top effort you can hold for as long as your race lasted. You hold a higher share for a short race than a long one, so a 5K time and a marathon time can give the same score.

Jack Daniels calls this score VDOT in Daniels' Running Formula. The two equations behind it, the oxygen cost of running speed and the drop-off in effort over time, come from his work with Jimmy Gilbert.

For the race times, the calculator runs the same equations backward: each is the time that gives your score at that distance, and the race you entered keeps its own time. For the training paces, it turns set shares of your score into speeds. Marathon pace is your marathon time spread evenly over the race.

We use the equations of Daniels' official calculator and match its results to the second at every whole score from 30 to 85. Outside that range the card tells you. This page does not reproduce the pace tables printed in Daniels' book.

What each Daniels training pace is for

Daniels' official calculator gives each of the five paces on the card a job.

Easy: warm-ups, cool-downs, recovery runs and most long runs, at a comfortable pace you can talk at. It can drift a little from day to day with how you feel, the weather and the ground.

Marathon: steady runs or long repeats at marathon race pace. Newer runners can also use it in place of easy pace on long-run days.

Threshold: comfortably hard running, as one steady tempo run or as repeated runs with short rests between them, called cruise intervals. It builds endurance.

Interval: hard but not all-out repeats of a few minutes each, with jog recoveries, to work your aerobic power.

Repetition: short, fast runs with long recoveries, so each one feels no harder than the last. They build speed and running economy, and relaxed form matters more than effort.