Tools
Free calculators. No sign-up, nothing stored, everything runs in your browser.
Acute:chronic workload ratio calculator
Calculate your ACWR from 7-day and 28-day training load. Includes the sweet-spot bands (0.80–1.30) and what values above 1.50 mean for injury risk.
Heart rate zone calculator
Calculate your five heart rate training zones, including Zone 2, from your age. Uses the Tanaka formula, with the Apple Watch zone model explained.
How many push-ups by age
Push-up test norms by age and sex, with percentile bands. See where your max set ranks and what counts as a valid repetition.
Readiness score calculator
Estimate a 0–100 daily readiness score from your HRV, sleep duration, resting heart rate and recent training load, and see how each input moves the number.
The real cost of every recovery tracker
Total cost of ownership for Whoop, Oura, Athlytic, Bevel, Gentler Streak and Body Vitals over 1–10 years. Hardware plus subscription, calculated.