Standard drinks

Body weight (lb)

Hours since first drink

Sex (for body-water estimate)

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General estimate for planning only — not medical advice. Consult a doctor about your specific situation.

Calculation details

Every figure above is calculated locally in your browser from the assumptions shown. No inputs are sent anywhere. See the methodology section below for how this tool works.

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How 3 drinks fall from 0.085% to 0.055% BAC — 3 drinks for a 160 lb man start at 0.085% and drop to 0.055%.

Method & verification

How This Tool Works

fact-checked against our calculation methodology

Calculation Method

Computes Estimated BAC from Standard drinks, Body weight, Hours since first drink and Sex.

Site methodology

BoringToolsKit methodology and verification standard

No unrelated authority link is added merely to make this page look sourced. Tool-specific external sources are shown only when they directly support the method, rate, or rule.

Assumptions to Verify

These tools provide general estimates for planning and education only.
They are not medical advice and not a substitute for a qualified healthcare professional.
Always consult your doctor or another healthcare provider about your specific situation.

Privacy: The calculation runs in this browser. Shared links contain the page address only, not your inputs or results.

A worked example, step by step

Take a 160 lb man who has 3 standard drinks and stops drinking 2 hours before checking. The calculator runs the Widmark formula: grams of alcohol divided by body water volume, minus the hours of elimination.

Step 1: 160 lb is 160 x 0.453592 = 72.57 kg. Step 2: 3 drinks carry 3 x 14 = 42 grams of pure alcohol. Step 3: for a male the body water factor r is 0.68, so the distribution space is 72.57 x 0.68 = 49.35 kg. Step 4: 42 / 49.35 = 0.851 grams per kg, divided by 10 to convert to a percent scale: 0.0851%.

Step 5: elimination over 2 hours removes 0.015 x 2 = 0.030%. Final estimate: 0.0851 - 0.030 = 0.055%. The same three drinks at hour zero, with no elimination time, would read 0.085%, which is why spreading drinks over 4 hours instead of 1 can move the same intake across the legal limit.

Where the estimate breaks down

The 0.015% per hour elimination is a midpoint. Published ranges run from roughly 0.010 to 0.025% per hour, so a fast metabolizer who drinks 4 beers over 3 hours could show 0.04% here while a slow metabolizer with identical inputs sits near 0.07%. The formula also assumes each drink is exactly 14 grams: a generous home pour of 7 oz wine is closer to 1.7 standard drinks, so three pours become five.

It cannot see food. Eating a meal before drinking typically lowers peak BAC by 20 to 40 percent because alcohol empties from the stomach slower, yet the inputs here have no field for it. The 0.55 water fraction for women and 0.68 for men are population averages across all body compositions; at the same weight and intake, real individuals can differ by well over the 0.02% that separates 0.06 from 0.08. Treat any single output as the center of a band roughly 0.02 to 0.03% wide, not a measurement.