Free Running Tool
Safe Weekly Mileage
Calculator
Enter your current training load, how long you’ve been running, and your goal. Get a week-by-week safe progression based on the 10% rule and acute:chronic workload research — with a plain-English injury-risk warning if you’re ramping too fast.
Your Numbers
What this calculator does
10% Rule
Max safe increase per week based on your experience level
ACR Warning
Flags when your target load exceeds safe acute:chronic ratio
8-Week Roadmap
Visual week-by-week progression to your goal mileage
Runner Profiling
Adjusts thresholds for novice vs. experienced runners
Fill in your numbers above and click Calculate Safe Mileage to get your personalized progression.
This calculator provides general training guidance only. It is not medical advice. Consult a sports medicine physician or physical therapist if you have existing pain or injury.