Weekly Mileage Progression
Calculator

The 10% rule suggests increasing weekly running volume by no more than about 10% from one week to the next, a guideline popularized in running culture to limit injury risk from ramping up training load too quickly. It's a rule of thumb, not a strict physiological law, but it remains a reasonably safe default.

The evidence is mixed: some studies have failed to show that runners following the 10% rule have significantly fewer injuries than those progressing faster, but abrupt, large increases in volume are consistently associated with higher injury risk. The rule works best as a conservative default rather than a precise threshold.

No, most experienced coaches recommend a build-up pattern with periodic step-back or recovery weeks, commonly reducing volume every third or fourth week, to let the body absorb the added training stress before continuing to progress.

It projects a sequence of weekly totals applying the chosen percentage increase compounded week over week, so you can see, for instance, how a 20-mile base grows over 8-10 weeks toward a marathon-training peak, while flagging when a step-back week should interrupt the progression.

Listen to fatigue, soreness, and sleep quality over a rigid percentage, since the 10% rule is a ceiling, not a mandate, and runners recovering from a break, illness, or with a history of injury should progress more conservatively regardless of what the formula suggests.