Widmark curve · breath mg/L · VN fines

🍺 Blood Alcohol Estimator

Log each drink with its time, or pick a quick count, and watch the alcohol curve (Widmark) in blood and breath: when it peaks, when it reaches 0, and which Decree 168 fine bracket you are in.

⚠️ Rough biological ESTIMATE — real BAC varies hugely with food, genetics and health. NEVER use this to decide whether to drive. In Vietnam the legal limit when driving is ZERO.

Hours since first drink1h
05080150+ mg/100 mL

Level over time: dashed lines are the 50 and 80 mg/100 mL fine thresholds; the faint dashed curve is a slow eliminator (β 0.10); 0 is the only level you may drive at

VN driving fines (Decree 168/2024, reference)

Widmark: each drink raises blood alcohol by grams ÷ (weight × r) × 1.055 (blood density, g/kg → mg/100 mL), r ≈ 0.68 (male) / 0.55 (female); it is absorbed over ~45 minutes and eliminated at a FIXED rate, on average ≈ 15 mg/100 mL per hour (β 0.15‰/h) but only ≈ 10 in slow eliminators (β 0.10): the page shows both marks. Breath mg/L = blood mg/100 mL ÷ 200, the 2000:1 ratio Decree 168 uses (50 ↔ 0.25, 80 ↔ 0.40). Coffee, showers or “sweating it out” do not speed it up; only time does.

Frequently asked questions

How much alcohol triggers a fine in Vietnam?
Under Decree 168/2024/NĐ-CP, any blood or breath alcohol concentration above zero is penalized — if you have drunk, do not drive; there is no safe threshold.
How long until alcohol leaves the body?
The liver clears alcohol slowly, roughly one unit per hour on average, but the rate varies with weight, sex, food and individual factors. This tool is only a rough estimate, not proof you are fit to drive.