Kairos is free to download and starts a 14-day free trial the first time you open it — no account, no card, no sign-up. When the trial ends, premium features lock until a single one-time purchase unlocks them forever. No subscription, no ads, ever.
Free forever — before, during, and after the trial: logging workouts, your full workout history, the complete exercise library, body measurements, PR celebrations mid-workout, importing shared plan files, up to 3 plans in your default group, and — most importantly — backup & restore. Your data is never held hostage: everything you record stays yours and stays exportable, whether or not you ever purchase.
Premium (open during the trial, unlocked permanently by the purchase): Coach Mode, Trends and records analysis, Target Goals, custom exercises, and sharing plans out of the app (receiving and importing them is always free). Two creation caps apply until you purchase, including during the trial: plans are capped at 3, and creating new groups is locked.
The purchase is handled by the App Store / Google Play under their payment and refund policies. And the web Plan Builder on this site is free for everyone, no app required.