English Endurance
Running Pace Zone Calculator
Calculate training zones and race pace equivalents from your threshold speed (LT2). Enter your threshold pace directly, or estimate it from a recent race result.
Zone spectrum — % of threshold speed
Training zones
| Zone | % of threshold speed | Pace / mile | Description |
|---|
Race pace equivalents
| Race | % of threshold | Pace range / mile | Finish time range | Notes |
|---|
Threshold speed = LT2/MLSS — the highest speed at which lactate production and clearance are balanced, typically sustainable for 45–60 min at maximal effort. Zone 2 ceiling (LT1) falls at ~80% of threshold speed. Race pace ranges adapt to your threshold pace via a sigmoid fitness model: aerobically developed athletes sustain a higher fraction of threshold speed at every distance due to superior running economy and fat oxidation. Marathon ranges tighten significantly for elite athletes and widen for recreational runners. Predictions represent plausible performance ranges, not guarantees — training specificity, conditions, and race execution all affect outcomes.