Live Widmark-style sketch with standard-drink decode and clearance timeline - so an estimate never pretends to be a drive decision.
Educational only. Not medical, forensic, or legal advice. If you drank, do not drive.
By Ahmet C. Toplutaş·Site owner & editor · Health education tools
Last updated May 21, 2026 · Reviewed May 21, 2026 · Planning estimates only - not tax, medical, or investment advice
01
Online BAC tools are easy to misuse as a green light. A modeled percentage is not a breathalyzer, not a blood test, and not legal advice. Food, medications, illness, body composition, drinking pace, and measurement error can move real impairment far from any classroom formula.
This page’s framing is estimate ≠ drive decision. The panel still shows a Widmark-style sketch so you can learn how inputs move the number - then it refuses to treat that number as permission. If you have been drinking, do not drive. Arrange another way home.
Decision framing: “How does a simplified model respond to weight, pour size, ABV, and time?” - never “am I legal / safe to drive?” For site-wide limits, see disclaimers.
02
The classic educational approach estimates alcohol mass from drinks × serving volume × ABV × ethanol density (~0.789 g/mL), divides by an estimated body-water mass (weight × Widmark r), expresses the result as a percentage, then subtracts a constant elimination rate (~0.015 BAC points per hour).
The sex selector only changes the population-average r factor commonly used in teaching models (~0.68 / ~0.55). It is not a clinical assessment of any person. Absorption is treated as already reflected in the “hours since start” simplification - real curves are messier.
03
People count “two beers” while pouring pints at 6–7% ABV. The panel’s standard-drink decode converts alcohol grams into an approximate U.S. standard-drink count (~14 g each) so the label serving and the actual ethanol load are not confused.
Other countries define standard drinks differently. Treat the decode as literacy, not as a universal bartending statute. If the decode says ~3.5 drinks and you thought you had “two,” the BAC sketch will look higher for a reason.
04
The unique timeline projects how long a constant 0.015/h sketch would take to fall from the current estimate toward a common adult U.S. per-se reference (0.08) and toward ~0.00. It exists to show that time is part of the model - and to make the danger of “I’ll wait one hour then drive” visible when the arithmetic still shows a long tail.
Feeling sober, drinking coffee, or taking a cold shower does not accelerate the elimination constant in this sketch - and none of those are a substitute for not driving. When the timeline marker arrives, the message is still: this was arithmetic, not clearance to operate a vehicle.
Limits differ by jurisdiction, age, and commercial licensing. The 0.08 marker is a reference tick for education in one common adult U.S. context - not your local law.
05
Impairment begins below common per-se limits for many people. Crash risk rises with BAC even when a number is “under the limit.” A calculator that stops at “below 0.08” as if that meant safe would be teaching the wrong lesson. This page refuses that frame.
Enforcement uses calibrated devices and statutes. This site uses a teaching formula. Those are different jobs. If you need legal or medical guidance, talk to a qualified professional - not a web form.
06
Example A · Two beers. Preset: 2 × 330 ml at 5%, 70 kg, 2 hours.
Read the standard-drink decode first - two cans near 5% are often close to two standards, but not always. Then read the BAC sketch and the clearance timeline. Even a “modest” session is not a drive decision.
Example B · Wine evening. Preset: 2 × 150 ml at 12%.
Restaurant pours are often larger than 150 ml. Raise volume and watch standard drinks and BAC jump - the decode exists for that surprise. Switch elapsed hours and watch the timeline stretch or shrink.
Example C · Cocktail round. Preset: 3 × 60 ml at 40%.
Spirits compress a lot of ethanol into a small glass. The alcohol-mass row makes that obvious. Compare the pre-metabolism sketch to the after-hours estimate - time reduces the model, it does not erase risk.
Example D · Hours later. Preset: larger beer session with 8 hours elapsed. The estimate may look lower; the drive rule does not change. Overnight sleep is not a certified clearance certificate.
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Stop here for literacy about Widmark inputs and standard drinks. Do not use this page for roadside decisions, workplace testing, medical care, or legal defense.
10
No. This is an educational Widmark-style sketch only. It cannot account for food, medications, illness, tolerance myths, measurement error, or legal standards in your jurisdiction. Never use any online calculator to decide whether you are safe or legal to drive. If you have been drinking, do not drive.
A modeled percentage is not a roadside test, not a lab result, and not permission. The clearance timeline shows how long a constant elimination-rate sketch would take to fall - it is still not a green light. The only safe driving decision after drinking is not to drive.
A simplified Widmark approach: alcohol mass from drinks × volume × ABV × 0.789 g/mL ethanol density, divided by body water mass (weight × r), expressed as %, then reduced by about 0.015 BAC points per hour. Real absorption and elimination vary widely between people and occasions.
The panel converts your pour into an approximate U.S. standard-drink count using ~14 grams of pure alcohol per standard drink. Label servings differ by country and by how full the glass actually is - the decode is a teaching aid, not a bartending rule.
The classic Widmark r factor uses different average body-water fractions (commonly ~0.68 vs ~0.55). That is a population average for an educational model - not a statement about any individual’s physiology, gender identity, or fitness.
It projects hours from the current estimate down to common reference marks (for example 0.08 and ~0.00) assuming a constant ~0.015 BAC/hour elimination. Metabolism is not constant, and feeling sober is not the same as a low estimate. It is not a countdown to legal driving.
No. Values hydrate from the URL on load, but the address bar updates only when you use Share or Copy. That keeps live editing calm and share links intentional.
LIVE BAC SKETCH
Estimate ≠ drive ↓Scene presets
Updates live. Estimate ≠ drive decision. Constant ~0.015 BAC/h elimination is a sketch, not your metabolism.
Estimated BAC (Widmark sketch)
0.025%
≈ 1.9 U.S. standard drinks · ~26 g alcohol · after 2 h
STANDARD-DRINK DECODE · POUR ≠ LABEL
ALCOHOL MASS
26.0 g
≈ STANDARD DRINKS
1.9
~14 g each (U.S. sketch)
A “beer” that is stronger or larger than the label serving counts as more than one standard drink. The decode makes that visible before the BAC %.
CLEARANCE TIMELINE · NOT A DRIVE COUNTDOWN
Now
0.025%
→ ~0.08 ref*
at/under sketch
→ ~0.00
+1 h 39 m
*0.08 is a common adult U.S. per-se reference only - limits differ by place, age, and vehicle class. This timeline assumes constant 0.015 BAC/h and is not permission to drive when the marker arrives.
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