Weekly Mileage Increase Calculator
Calculate safe weekly mileage increases using the 10% rule and custom rates.
10% Rule Formula
Next Week = Current Week × (1 + rate/100)
Cutback Week = Week 3 × 0.80 (20% reduction)
Apply cutback after every 3 build weeks for optimal adaptation.
Increase Rate Guide
| Rate | Best For | Risk |
|---|---|---|
| 5% | Injury-prone, high mileage runners | Very Low |
| 10% | Most runners — standard guideline | Low |
| 15% | Experienced runners with good history | Moderate |
| >20% | Not recommended for sustained use | High |
Frequently Asked Questions
-
The 10% rule states that weekly mileage should not increase by more than 10% from one week to the next. E.g. 30 miles this week → max 33 miles next week. Helps prevent overuse injuries.
-
Evidence is mixed. Some studies support it; others show 10% can still be too aggressive for injury-prone runners. It's a guideline, not a guarantee. Experienced runners may tolerate higher increases.
-
Beginners may increase faster from very low bases (e.g. 10 to 12 miles). But as mileage grows, the 10% rule becomes more important. Over 30 miles/week, stay at or below 10%.
-
Follow a build-cutback pattern: 3 weeks of increasing (10% each) then 1 cutback week (reduce 20%). This allows adaptation and recovery before building again.
-
Count all running miles. Walk breaks in run/walk training count as partial. Cross-training (cycling, swimming) does not count toward running mileage but adds overall load.
-
A planned recovery week where mileage drops 20–30% below the previous week's total. Typically every 3–4 weeks. Allows tissue repair and adaptation before the next build phase.
-
Race week: reduce mileage by 20–30% (taper). Post-race: 1–2 easy recovery weeks at reduced mileage before resuming building. Never increase mileage the week after a hard race.
-
Most coaches recommend at least 3–4 weeks of consistent mileage before increasing. Consistency matters more than current volume. A solid base prevents sudden load spikes.
-
Off-season base building allows conservative increases. Still follow 10% guideline but you can maintain higher mileage for longer before needing a cutback week.
-
After a missed week, return to the mileage from 2 weeks ago (step back, not forward). After illness or injury break over 1 week, return at 50–60% of previous mileage.
-
The percentage rule is the same — 10% regardless of unit. If running in km, 50 km this week → max 55 km next. Calculator works with any unit.
-
At 10% per week, doubling takes ~7–8 weeks (1.1^7 ≈ 2.0). With cutback weeks, allow 10–12 weeks to safely double mileage while maintaining adaptation.