The One Rep Max vs IronOS

The One Rep Max calculator uses a little previous knowledge to give you an approximation of what amount of weight you could lift one time. Use this value to push yourself while remaining safe, and chart your progress along the way.

Train for the next twenty years, not the next twelve weeks. IronOS is a free strength training log for lifters who measure progress in years — pre-calculated warmups, automatic plate math, and RPE-based autoregulation. Chase PRs while they're coming, and track what you're holding onto when they slow down. Work with your coach, coach yourself for free, or let AI coach you. LOG WITH PRECISION Pre-calculated warmups, automatic plate math, and RPE-based autoregulation. IronOS shows you exactly what to load, tracks your rest, and captures every rep. Mark a set as it felt and the app tells you whether you were dialed in or overshot. No spreadsheets, no guesswork. DURABILITY SCORE An age-graded strength standard — the thing masters runners have had for forty years and lifters never got. Built on DOTS normalization and IPF age coefficients, the same standards powerlifting federations use, it shows how your current strength compares to an age-adjusted benchmark without ever testing a 1RM. A second measure of progress, one that keeps moving even when your PRs don't. BUILT FOR BARBELL TRAINING Configurable bar weights, plate inventory, cable stack settings, and deadlift start height. Equipment that matches your gym, not a generic default. TRACK WHAT MATTERS PRs tracked automatically across every rep range — squat, bench, deadlift, and every accessory you log. The Progress tab charts your top sessions over time for each lift. AI COACHING A guided intake learns your schedule, equipment, and goals, then IronOS writes your program — its own programming logic, powered by Claude. It reads your actual training log: your logged sets, your weight progression, your feedback on how each session went. Check-ins on fatigue, sleep, and life stress adjust volume and intensity. Miss a day and your week reshuffles itself. Free for 14 days. WORKING WITH A COACH Your coach sees every set, adds notes to individual exercises, leaves session feedback, and reviews your form checks — all in one place. Record and upload video mid-workout with full context attached. APPLE HEALTH Bodyweight syncs automatically, so your Durability Score stays current. Built for lifters who care about the long game. SUBSCRIPTION IronOS is free to use. AI Coaching is an optional auto-renewing subscription: free for 14 days, then $7.99/month. Payment is charged to your Apple ID account when the free trial ends. Your subscription renews automatically unless canceled at least 24 hours before the end of the current period. Cancel during the trial and you won't be charged. Manage or cancel anytime in your Apple ID account settings. Terms of Use: https://www.ironos.app/terms Privacy Policy: https://www.ironos.app/privacy