Track what and when.
Tap below immediately after finishing a drink. It records the exact local time automatically. You can edit the details afterward.
Standard 1.5 oz shot glass · 80 proof (40% alcohol). Select your estimated pour:
Full shot = 1 U.S. standard drink (14 g alcohol). Tapping records the current time.
Add a drink
Choosing a size automatically sets standard drinks. Previous records remain unmeasured unless you edit them.
Model-based BAC estimate
Enter your weight and physiology setting to enable the educational estimate.
Not a sobriety test. This is a rough calculation, not measured BAC. It can be too low, especially soon after a drink. Never use this number or a consumer breathalyzer to decide whether to drive.
When to use your breathalyzer
20-minute waitAfter finishing your last sip of beer, wine, or spirits, tap below. Do not start the timer when you begin drinking.
Start the timer after your last sip.
Breathalyzer testing directions
- Finish your last drink, then start this timer.
- Wait at least 20 minutes after your last sip. During the wait, do not eat, drink anything, smoke, vape, or use mouthwash.
- After 20 minutes, follow your device's testing instructions, including its required breath sample and measurement units.
- Record the reading in the Daily timeline. Keep it separate from the app's modeled BAC.
Not a sobriety countdown. This only reduces false-high readings from mouth alcohol. Your BAC can still rise; neither result tells you whether it is safe to drive.
Daily timeline
Times between recorded drinks will appear here.
BAC comparison · selected day
━ Delayed model ━ Old v2.3 model ● Device reading
Hollow dots: less than 20 minutes after a completed drink.
The optional band varies recorded amounts only (±20% with pour details, ±30% without). Physiology and absorption assumptions stay fixed. It is not an overall BAC accuracy range. Device values can lie outside it.
7 days
30 days
overall
Calendar.
Choose a day to see drinks, intervals, readings and symptoms.
Colored dates contain a drink record or symptom entry. A blank date does not mean zero drinks.
History.
Recorded days, newest first. Tap a day to view drinks, intervals, and symptoms.
Profile & backup.
BAC estimate settings
Used only for a simplified calculation. Drink amounts matter: a half shot of 80-proof whiskey is 0.5 U.S. standard drinks, not 1.
The formula uses average alcohol distribution factors, not an individual's measured body composition.
App updates
Drink Log v2.4 · Chart & model correction · build 4. Check for the latest deployed version without restarting your phone. Saved records and the breathalyzer timer stay on this device. Finish and save any open form first.
Export & restore
Drink, symptom and device-reading records stay in this phone or browser, not in Cloudflare. Back up before changing phones or clearing app storage. Updates on the same Cloudflare URL preserve local records.
About the estimate
One U.S. standard drink ≈ 14 g ethanol. Pours with volume/ABV use oz × 29.5735 × ABV/100 × 0.789 g ethanol. Unknown pours retain their recorded standard drinks × 14 g. Spirits are modeled as a shot consumed over 30 seconds before the completion timestamp. Other drink types retain a 15-minute consumption assumption. First-order absorption has a 30-minute time constant after ingestion; finishing a shot does not mean it is absorbed. These durations are assumptions, not measured start/absorption times. Distribution factors remain 0.68 male / 0.55 female. Elimination now slows at low concentrations using Michaelis–Menten kinetics: rate = 0.015 × BAC / (0.008 + BAC) %BAC/hour, with one-minute integration. This avoids removing alcohol at a full constant rate while very little has been absorbed. Parameters are population assumptions, not fitted to your device. Kinetic model reference. The main number is the central estimate. The optional band varies dose ±20% for pour metadata or ±30% without, holding physiology fixed. These percentages are sensitivity assumptions, not measurement precision. It excludes uncertainty in distribution, metabolism, absorption, missed drinks and device error; it is not a confidence interval or an overall accuracy bound. The previous combined-extremes envelope has been removed rather than presented as a likely personal BAC range. Untimed legacy records are preserved and excluded. Current profile applies to all historical estimates. No automatic calibration. Elimination variability reference.
A device reading is stored as a separate observation. It does not automatically calibrate the estimate or verify a device's accuracy.
Alcohol-related impairment can occur at any displayed BAC. Do not use this app to assess driving or machinery safety.
Drink Log v2.4 • Free • No accounts • No ads • No tracking • Private on-device data