Cutoff: Caffeine & Sleep

Cutoff shows how much caffeine is actually in your body right now, and estimates your wind-down window — the range of times it typically drops below the level that starts affecting sleep. A range, not a single time. Caffeine's half-life varies from about 2 to 10 hours between people, so a confident "you're clear at 9:47 PM" is false precision. Cutoff shows an honest window instead, and you can tune it to match what you actually notice. WHAT MAKES CUTOFF DIFFERENT • One tap to log. Coffee, espresso, cold brew, tea, energy drinks, or a custom amount. • A live curve. Watch caffeine rise and fall through your day, modelled the way pharmacology actually does it — absorbed over an hour, then cleared at a steady rate. • Two honest answers. Most apps show one confident cutoff time. Cutoff shows both its own estimate and what sleep research suggests — which often points earlier — and lets you see where they disagree, rather than pretending they agree. • A screen that reads your state. The background warms as your caffeine climbs toward your daily limit, so you can tell where you stand at a glance. • Trends that build over time. A 13-week intake heatmap, your typical day, and when you usually have your first cup. • Sleep, side by side. Connect Apple Health to see your sleep next to your caffeine. If you use Oura or Whoop, their sleep flows into Apple Health too. Shown honestly — not as cause and effect. PRIVATE BY DESIGN Everything stays on your device. No account, no sign-in, no server, no analytics, no ads. Cutoff has no networking code at all — it cannot send your data anywhere. Export your log as a CSV or delete everything, any time. Cutoff is for general information and self-awareness. It doesn't diagnose, treat, or prevent anything, and it can't tell you how you'll sleep — caffeine is one of many things that affect that.