Treadmill Pace Chart

Grade changes the energy cost of running steeply. The table below converts common belt paces at grades from 1% to 10% into the effective flat pace — the outdoor-flat pace that costs your body the same energy, from the running energy-cost curve fitted by Minetti and colleagues (J Appl Physiol, 2002). A 9:00/mi belt session at 4% is doing the work of roughly 7:17/mi flat.

Indoors there is no air resistance, so a 0% belt is slightly easier than flat ground outside. In the most-cited study on the topic, Jones and Doust (1996) measured oxygen uptake at treadmill grades of 0%, 1% and higher against outdoor running, and found that a 1% grade reproduces the energy cost of outdoor flat running at typical training and racing speeds. That single finding is why virtually every coach and every treadmill conversion chart treats 1% as “honest flat”.

The practical rule: for easy runs the difference barely matters, but for interval or tempo work at faster than about 7:30/mi, set the belt to 1% and the numbers on this chart describe your real outdoor pace.

The effective-pace column uses the peer-reviewed energy-cost curve from Minetti et al. (2002), which fits the gross cost of running C(i) — joules per kilogram per metre — to grade i. Flat running costs C(0) = 3.6 J/kg/m; at 5% the curve gives 4.69 J/kg/m, about 30% more. At equal energy cost, the flat-equivalent pace is belt pace × 3.6/C(i).

Be honest about what that number is: a group-level energetic equivalent, fitted from a small sample of trained runners. It does not know your running economy, your strength on hills, or the fact that treadmill belt mechanics differ subtly from overground running. Treat it as a planning tool for comparing sessions — not as a precise physiological prediction. The full derivation and its limits are on the methodology page.