Private, on-device log
Daily caffeine tracker
Log drinks as you have them, then see a transparent estimate of what may remain now and at bedtime. Your log stays in this browser and is never sent to CaffCalc.
Quick log
View weekly reportSearch and choose a serving to log it now. You can undo or edit its time immediately.
Search a drink to log now
Filter by brand or category
Showing up to 10 servings. Refine your search to find another size.
Star a drink on its page or in the tools to keep it here.
Add a drink
What did you have?
Your assumptions
Bedtime and half-life
Five hours is a modelling default, not a personal measurement. Clearance varies substantially. Read the method and limitations.
Live estimate
Caffeine remaining through the day
This line adds each logged dose at its consumption time and applies your selected half-life independently. It is a mathematical estimate, not a blood-level reading.
View accessible curve data
| Time | Estimated caffeine |
|---|---|
| 6:00 | 0.0 mg |
| 6:30 | 0.0 mg |
| 7:00 | 0.0 mg |
| 7:30 | 0.0 mg |
| 8:00 | 0.0 mg |
| 8:30 | 0.0 mg |
| 9:00 | 0.0 mg |
| 9:30 | 0.0 mg |
| 10:00 | 0.0 mg |
| 10:30 | 0.0 mg |
| 11:00 | 0.0 mg |
| 11:30 | 0.0 mg |
| 12:00 | 0.0 mg |
| 12:30 | 0.0 mg |
| 13:00 | 0.0 mg |
| 13:30 | 0.0 mg |
| 14:00 | 0.0 mg |
| 14:30 | 0.0 mg |
| 15:00 | 0.0 mg |
| 15:30 | 0.0 mg |
| 16:00 | 0.0 mg |
| 16:30 | 0.0 mg |
| 17:00 | 0.0 mg |
| 17:30 | 0.0 mg |
| 18:00 | 0.0 mg |
| 18:30 | 0.0 mg |
| 19:00 | 0.0 mg |
| 19:30 | 0.0 mg |
| 20:00 | 0.0 mg |
| 20:30 | 0.0 mg |
| 21:00 | 0.0 mg |
| 21:30 | 0.0 mg |
| 22:00 | 0.0 mg |
| 22:30 | 0.0 mg |
| 23:00 | 0.0 mg |
Today
Drink log
Add a source-backed drink or enter the value printed on your product label.
Stored on this device
Seven-day pattern
Unlogged days are unknown. This overview divides recorded intake by all seven days; the weekly report shows averages over recorded days and highlights missing data.
| Date | Drinks | Total | At bedtime | Last drink |
|---|---|---|---|---|
| Thu 3 Sept | 0 | 0.0 mg | 0.0 mg | — |
| Fri 4 Sept | 0 | 0.0 mg | 0.0 mg | — |
| Sat 5 Sept | 0 | 0.0 mg | 0.0 mg | — |
| Sun 6 Sept | 0 | 0.0 mg | 0.0 mg | — |
| Mon 7 Sept | 0 | 0.0 mg | 0.0 mg | — |
| Tue 8 Sept | 0 | 0.0 mg | 0.0 mg | — |
| Wed 9 Sept | 0 | 0.0 mg | 0.0 mg | — |
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