BloodLevel: Caffeine Tracker

Espresso at four, bed at eleven — how much caffeine is still working by then?

BloodLevel answers exactly that. Log coffee, tea or an energy drink in two taps, and a pharmacokinetic model computes live how much caffeine is active in your body right now, when it peaks, when you’re sleep-ready — and how much coffee still fits today.

YOUR CURVE, LIVE
• Active caffeine in mg — not what you drank, but what is still working right now
• History and forecast in one curve: scrub across it to read the value at any moment, hours ahead
• Peak with time of day, daily total against the 400 mg guideline

SLEEP-READY — TO THE MINUTE
• Sleep threshold: you count as sleep-ready once your active caffeine drops below it
• Sleep budget: how much caffeine still fits right now without keeping you up at midnight?
• Last coffee: the time until which an espresso still fits into tonight
• Optional notifications when you’re sleep-ready — and a “last call for coffee” 15 minutes before the cutoff

LOGGED IN TWO TAPS
• 13 drinks with real caffeine figures: Espresso, Double Espresso, Cappuccino, Latte, Filter Coffee, Coffee to go, Cold Brew, Black Tea, Green Tea, Matcha, Energy Drink, Cola, Decaf
• Touch and hold to adjust the amount, save your own drinks
• Quick log from the home screen, backdating with a time chip, undo included

COUNTDOWN ON YOUR LOCK SCREEN
A Live Activity counts down to sleep-ready — on the Lock Screen and in the Dynamic Island. Plus widgets with your current level and a mini curve for Home and Lock Screen.

YOUR METABOLISM
The half-life is adjustable: about 5 hours on average, shorter for smokers, much longer during pregnancy or on the pill. The app computes with your value.

STATISTICS THAT UNDERSTAND CAFFEINE
Sleep check (how many nights over the threshold), days within the guideline, average first and last cup, caffeine-free days, a 12-week heatmap, weekday and time-of-day profiles, most-logged drinks.

APPLE HEALTH
If you like, every drink is written to Apple Health as caffeine. And “Coffee & body” lays your model over your real data: how long, how interrupted and how deep did you sleep on nights with more vs. less caffeine at sleep onset? How do resting heart rate and HRV respond? The app compares honestly — associations only, and only with enough nights — and suggests a personal sleep threshold from your own data.

PRIVATE BY DESIGN
No account, no cloud, no trackers, no ads. Everything stays on your iPhone — including anything read from Health. The CSV export is yours.

IMPORTANT
BloodLevel computes model estimates based on population averages and the caffeine content of typical drinks. The app measures nothing in your body, is not a medical device, and is no substitute for medical advice.