Caffeine cutoff app
Your last coffee has a deadline.
Reps shows how much caffeine is still in your system right now, and the latest time you can have more without wrecking tonight's sleep — tuned to your own body's speed, not a generic rule of thumb.
iPhone · Apple Watch Series 6 and later
Know exactly when to stop
Caffeine has a half-life. Most people ignore it until 2 a.m.
Reps tracks the caffeine that's still active in your body as the day goes on, so instead of guessing whether that afternoon coffee was a mistake, you can actually see the running total come down. From there it works out your personal cutoff — the latest time you can have more before it starts stealing from tonight's sleep.
The point isn't to make you quit coffee. It's to move that last cup earlier by an hour when it matters, so you fall asleep faster and wake up with a better recovery score. Small change, real payoff — and Reps makes the timing obvious instead of a guess.
Active caffeine, live
See how much is still in your system right now, not just what you drank — the total decays through the day as your body clears it.
A personal cutoff time
Reps estimates the latest time you can have caffeine without it cutting into tonight's sleep, tuned to how fast you clear it.
Tied to your sleep
The cutoff is built around sleep impact — and it feeds the same recovery picture as your Apple Watch sleep and HRV.
Quick to log
Add a coffee in seconds so the running total stays honest. It sits alongside your food, water, and macros.
Part of the whole recovery picture
Late caffeine is one of the quiet reasons a good day of training turns into a bad night of sleep. Because Reps also turns your Apple Watch's sleep, HRV, and training load into a daily Readiness Score, it can connect the dots the next morning — and Rex, the AI coach, can answer questions like "why did I sleep badly last night?" from your real data instead of a generic tip.
Caffeine sensitivity varies from person to person. Reps gives an informed estimate to help with timing — it isn't medical advice.
Common questions
How does Reps know my caffeine cutoff time?
Reps models how much caffeine is still active in your system from what you log and estimates the latest time you can have more without it bleeding into tonight's sleep. It tunes the estimate to your own body's speed rather than a fixed rule.
Do I have to log every coffee?
You log your caffeine so Reps can track what's still active. The more consistently you log, the more accurate the running total and the cutoff time become.
Does the caffeine tracking connect to my sleep?
Yes. The cutoff is tied to sleep impact, and because Reps also reads your Apple Watch sleep and recovery, late caffeine is part of the same picture your Readiness Score is built from.
Is this medical advice?
No. Reps gives you an informed estimate to help you make better choices about timing, not medical advice. Sensitivity to caffeine varies, so treat it as guidance.
Caffeine cutoff app
Protect tomorrow's score.
Move your last coffee to the right hour. Free to try, with the Apple Watch you already own.
Free to download • Syncs with Apple Health