Long Run Distance Calculator

About this calculator

Distance-running coaches use a well-established rule of thumb that the weekly long run should make up roughly 25-30% of total weekly mileage — a runner covering 40km a week would target a long run of about 10-12km, structured to build aerobic endurance without eating into the recovery needed for the rest of the week’s training.

This percentage-based approach appears in nearly every popular marathon and half-marathon training methodology, from Jack Daniels’ running formula to Hal Higdon’s beginner and intermediate plans, precisely because a long run that grows too large relative to weekly volume is one of the most common causes of overuse injury and burnout in distance runners. Coaches use it as a guardrail when a runner wants to push their long run further: if it starts exceeding roughly a third of the week’s total mileage, the standard advice is to build up total weekly volume first, rather than the long run in isolation.

Enter your total weekly running distance, and this calculator returns the recommended long-run distance based on the standard 25-30% guideline.