Caffeine tracker for better sleep
Know exactly when your last coffee will let you sleep
HalfCup uses proven half-life decay modeling to show when caffeine will clear your system. Log a drink in one tap, watch your decay curve, and see your “sleep-ready by” time — 100% offline, no account, no subscription.
$4.99 one-time. No subscription. No ads.
Illustrative decay curve — scrub the real one in the app
Tired of bedtime anxiety?
That 3 pm coffee felt harmless. At 11 pm you’re staring at the ceiling, wondering if it was the caffeine. Stop guessing.
The guessing game
- No idea how much caffeine is still in your system right now
- “Last coffee by 2 pm” rules that ignore your personal metabolism
- Hidden caffeine in tea, soda, chocolate, and pain relievers
- Trackers that demand accounts, subscriptions, and your data
The HalfCup answer
- A real-time decay curve built on peer-reviewed caffeine pharmacokinetics
- A “sleep-ready by” time after every drink, plus today’s last safe caffeine time
- 250+ drinks covered — coffee, tea, energy drinks, soda, pills, chocolate, gum
- 100% offline, zero data collection, $4.99 once
Everything in the app, nothing you don’t need
Every feature below is in HalfCup today — no roadmap promises.
Personalized half-life
Everyone processes caffeine differently. Set your half-life anywhere from 2 to 10 hours, with a 30-minute absorption window for accurate modeling.
Sleep-ready time
See your “sleep-ready by” time after every drink, and the last safe caffeine time for today based on your bedtime.
Scrubbable decay curve
Watch your caffeine level drop in real time, and scrub the timeline to check your level at any future hour.
250+ drink database
Espresso, latte, cold brew, matcha, chai, Monster, Red Bull, Celsius, colas, caffeine pills, chocolate, gum — plus custom drinks you create.
One-tap logging
Quick-add favorites with a single tap. Partial servings (half a can, 2.5 oz espresso) with decimal precision, in oz or ml.
Private by design
100% offline. No account, no cloud sync, no analytics, no crash reporting. Export your history as a PDF anytime.
Daily limit warnings
Set your bedtime, wake time, and daily caffeine goal (default 400 mg, the FDA maximum) and get warned when you exceed it.
History & statistics
Today, 7-day, and 30-day views with daily averages, consumption trends, and peak-time analysis. Edit or delete past entries anytime.
How HalfCup helps you sleep better
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Log what you actually drink
Coffee, tea, an energy drink, a cola, even chocolate or an Excedrin — quick-add it in seconds from the 250+ item database or your favorites.
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See the science, not a guess
HalfCup models how caffeine decays in your body using half-life pharmacokinetics tuned to your personal 2–10 hour setting.
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Get your sleep-ready time
After every drink you see exactly when you’ll be sleep-ready — and whether that 3 pm coffee will ruin tonight’s sleep before you drink it.
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Spot your patterns
7- and 30-day trends, daily averages, and peak-time analysis show where your caffeine really comes from, so cutting back gets easier.
Who it’s for
Frequently asked questions
HalfCup uses half-life decay modeling built on peer-reviewed caffeine pharmacokinetics, with a 30-minute absorption window. After every drink you log, it shows a “sleep-ready by” time and a visual decay curve you can scrub through to check your caffeine level at any future time.
No. HalfCup is a one-time purchase of $4.99. Pay once, own forever — no subscriptions, no ads, and no upsells.
Yes. HalfCup runs 100% offline with zero data collection: no account, no cloud sync, and no analytics or crash reporting. Your data stays on your device, and you can export it as a PDF anytime.
No. HalfCup tracks coffee, tea (black, green, matcha, chai), energy drinks (Monster, Red Bull, Celsius, Bang), soda and cola, caffeine pills like Excedrin, chocolate, and gum. It ships with accurate caffeine amounts for 250+ drinks, and you can create custom entries for anything missing.
Yes. You can adjust your personal caffeine half-life anywhere from 2 to 10 hours to match your sensitivity, so the decay curve and sleep-ready time reflect your metabolism rather than a one-size-fits-all average.
Yes. HalfCup supports partial servings — half a can, 2.5 oz of espresso — with decimal precision, and you can choose oz or ml units. Quick-add favorites let you log in one tap.
No. HalfCup provides informational and educational tools only and is not intended to provide medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your caffeine consumption, especially if you are pregnant, nursing, have a medical condition, or take medications.
Caffeine & sleep guides
Evergreen, science-grounded reading on how caffeine actually works — no app required.
Caffeine half-life, explained
How long caffeine really stays in your system, why the 5-hour average misleads, and what changes your personal number.
Read the guide →When to stop drinking coffee before bed
How to find your personal caffeine cutoff time instead of borrowing someone else’s rule of thumb.
Read the guide →How much caffeine per day is safe?
What the 400 mg FDA guideline means in real drinks, and how to tell when you’re over your own limit.
Read the guide →Hidden sources of caffeine
Decaf, chocolate, pain relievers, gum, and “calm” teas — where caffeine sneaks into your day uncounted.
Read the guide →Simple. Accurate. Private.
Take control of your caffeine intake today — and stop guessing about tonight’s sleep.
$4.99 one-time · iOS 15.1+ · iPhone & iPad
Medical disclaimer: HalfCup provides informational and educational tools only. It is not intended to provide medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your caffeine consumption, especially if you are pregnant, nursing, have a medical condition, or are taking medications.