Brazil drink-driving limit: frequently asked questions | SmartBAC

Brazil enforces zero tolerance for alcohol at the wheel: any detectable amount is grounds for penalty. In practice the law works through two thresholds. From 0.05 mg/L of breath — the reading on the device itself, before the margin of error is taken off — the driver commits a very serious administrative offence under article 165 of the Brazilian Traffic Code (CTB).

The second threshold is criminal. If the reading is 0.34 mg/L or higher, it stops being a fine and becomes a traffic crime under article 306 of the CTB, with the possibility of arrest on the spot. Between 0.05 and 0.33 mg/L the penalty is administrative; from 0.34 mg/L it is criminal. These figures apply to the breath test — a blood test uses a different scale, in grams per litre.

There is no exact conversion, but you can estimate. How many beers equal 0.05 mg/L depends on your weight, sex, metabolism and how long ago you drank. In practice a single 350 ml can of 5% beer is enough to put many people at that level, and for lighter people it can push them well past it.

So the answer is an uncomfortable one: one beer can be enough. Because Brazil applies zero tolerance, there is no "safe" quantity that guarantees you stay under the threshold — the margin between drinking a little and committing an offence is too small to work out in your head. Use the calculator on this page for an estimate based on your own details and elapsed time. If you are driving, the safe amount is zero.

If the test shows a reading between 0.05 and 0.33 mg/L, the driver commits a very serious offence: a fine of R$ 2,934.70, a 12-month driving ban and seven points on the licence. The vehicle is impounded until a licensed, sober driver can take over.

For a repeat offence within 12 months the fine is doubled. And if the reading is 0.34 mg/L or higher, the conduct is no longer merely administrative and becomes a traffic crime, punishable by six months to three years of detention, on top of the fine and a court-ordered licence suspension. The administrative and criminal penalties are cumulative — one does not replace the other.

You can refuse — nobody can be physically compelled to take the test, and no one is obliged to produce evidence against themselves. But refusing is not a way out: it is treated under article 165-A of the Brazilian Traffic Code as a very serious offence, carrying exactly the same administrative penalties as blowing and failing.

That means a fine of R$ 2,934.70, a 12-month driving ban and impoundment of the vehicle. Refusing also does not prevent prosecution: the officer can record signs of intoxication in a formal report, and video, witnesses and the driver's own behaviour can all be used as evidence. In short, refusing only keeps the device's exact number out of the file — it does not avoid the penalty.

Yes. A reading between 0.05 and 0.33 mg/L carries an automatic 12-month suspension of the right to drive, applied administratively alongside the fine. This is not discretionary — it follows from the offence being classed as very serious under article 165 of the CTB.

At 0.34 mg/L or above, or where you refuse the test, the consequences escalate. A criminal conviction under article 306 can bring a court-ordered suspension or outright revocation of the licence, separate from and additional to the administrative ban. Foreign drivers are not exempt: an international permit or foreign licence can be seized and the right to drive in Brazil withdrawn for the same period, and the offence may be reported to your home licensing authority.

Blowing is not compulsory in the sense that you cannot be forced to do it. But in the sense that matters in practice, it effectively is: refusing carries the same administrative penalty as being caught over the limit, so there is no legal advantage in declining.

At a checkpoint the officer can establish intoxication by other means besides the device — a clinical examination, a blood test, video, witnesses, or simply recording the observed signs in a formal report, as the Brazilian Traffic Code provides for. The stop itself is lawful and does not depend on your consent. All you are really deciding is whether the breathalyzer's number joins the file; the penalty can follow either way.

An online calculator gives an estimate, not a legal measurement. It applies established science — usually the Widmark formula — to your weight, sex, what you drank and how long ago. That is enough to show the order of magnitude and the shape of the curve, but the real figure can differ by ±20% or more.

The variation comes from things a formula cannot see: your metabolic rate, how much food was in your stomach, hydration, medication, liver condition and how quickly you drank. None of these are captured by a few input fields. Treat the result as a planning aid — useful for deciding whether you are anywhere near the limit — and never as evidence that you are safe to drive. Only an approved, calibrated device produces a legally meaningful number.

They are the same device. Etilômetro is the technical and official term, used in the Brazilian Traffic Code and in CONTRAN regulations; bafômetro is the colloquial name that stuck in everyday Brazilian Portuguese. There is no difference in equipment or legal standing between the two words.

The device measures alcohol concentration in alveolar air — the air from deep in the lungs — and expresses it in milligrams of alcohol per litre of breath (mg/L). To carry legal weight, the unit must have model approval from Inmetro and a current metrological verification. That is why a personal device bought online is useful as a rough guide but does not carry the same authority as an official roadside test.

The driver blows steadily into a disposable mouthpiece attached to the device, which analyses air from deep in the lungs. The result appears within seconds, expressed in milligrams of alcohol per litre of alveolar air (mg/L). The procedure is quick and non-invasive, and the measured value can be used as evidence in an infringement notice.

A few things affect the reading. It is advisable to wait about 15 minutes after your last sip, because residual alcohol in the mouth can inflate the result. Mouthwash, some cough syrups and even burping can produce artificially high readings. A driver who disputes the figure can ask for a second test or a blood test, which is more precise because it measures concentration directly in the bloodstream.

In Brazil the etilômetro reports its result in milligrams of alcohol per litre of alveolar air (mg/L) — the unit cited in infringement notices and in articles 165 and 306 of the Brazilian Traffic Code. A blood test instead uses grams per litre (g/L), a different scale with larger numbers.

Internationally you will also meet per mille (‰), common in Europe, and percent BAC (%), used in the United States. The rough equivalences are: 0.05 mg/L of breath ≈ 0.1 g/L of blood ≈ 0.1 ‰ ≈ 0.01% BAC. The calculator on this page estimates alcohol in blood and shows it in g/dL — the unit Brazil's most-used calculators work in (0.01 % BAC = 0.01 g/dL). It is not directly comparable to a breathalyser reading: this estimates blood, the etilômetro measures exhaled air, and they are different biological media. To convert: 0.01 g/dL ≈ 0.1 g/L of blood ≈ 0.05 mg/L of breath. In practice the article 306 crime begins at 0.6 g/L of blood — 0.06 g/dL on this calculator.

Every etilômetro has a recognised margin of error, and the law already accounts for it. The CONTRAN resolution governing these devices requires the margin to be deducted from the reading before an infringement is issued — and 0.05 mg/L and 0.34 mg/L are the measured reading — the number on the display — not the corrected figure: the margin comes off them, not the other way round. In the Anexo I reference table a reading of 0.34 mg/L gives a considered value of 0.30 mg/L, exactly the article 306 threshold, and a reading of 0.05 mg/L gives 0.01 mg/L.

In practice this works in the driver's favour: the value recorded on the notice is always equal to or lower than what the device showed. For a result to be valid, the unit must hold model approval from Inmetro and a current metrological verification. If there is doubt about calibration, the notice can be challenged administratively, or a blood test requested, which does not depend on converting from breath.

It depends on your body and how much you drank. On average the body clears one unit of alcohol every 1 to 2 hours — roughly a can of beer or a glass of wine. After moderate drinking it is sensible to wait 6 to 12 hours before getting behind the wheel.

After heavy drinking the safest course is not to drive until the next day, and even then with care: someone who drank late can still be over the limit the following morning while already feeling fine. The feeling of being sober does not track the actual fall in your reading. Nothing speeds the process up — only time works. When in doubt, take a ride-hailing app, a taxi or public transport.

Alcohol is typically detectable in alveolar air for up to 12 hours after drinking, depending on how much was consumed and on individual metabolism. After a small amount a few hours is enough; after a long night the device can still register meaningful values the next morning.

Elimination happens at a fairly constant rate — around 0.015% BAC per hour — and that speed cannot be increased by anything you do. Weight, sex, food, hydration and medication change the starting point and the shape of the curve, but not the underlying logic: the liver processes alcohol at its own pace. This is why a few hours' sleep is no guarantee of being under the limit.

There is no proven way to speed up alcohol elimination. Coffee, a cold shower, exercise, cold water and fatty food do not lower your blood alcohol level — at best they make you feel more alert, which is more dangerous still, because it creates a false sense of being fit to drive.

The liver metabolises alcohol at its own, essentially fixed rate, and only time brings the level down. Drinking water and eating before or during drinking can reduce the peak you reach and the next day's discomfort, but they do not shorten elimination. If you have been drinking and need to get somewhere, the only safe decision is not to drive: use an app, a taxi, public transport, or agree a designated driver in advance.

One unit of alcohol is roughly 10 grams of pure alcohol. In Brazil that works out at about one 350 ml can of beer, a 100 ml glass of wine or a 30 ml measure of spirits. It is the same quantity of alcohol served in very differently sized containers.

Thinking in units helps you compare drinks, but it does not make any amount safe for driving. The effect of each unit shifts with weight, sex, metabolism and what you have eaten. And because Brazil applies zero tolerance, even a single unit can be enough to cross the threshold for an infringement. Counting units is a way to understand your own drinking — not a way to work out how much you can have before driving.

On average the body clears the equivalent of one drink every 1 to 2 hours, but complete elimination depends on how much was consumed. After a heavy night, alcohol can still be present 12 hours or more later, and the level only reaches zero once the liver has processed everything that was drunk.

Age, weight, sex, food, hydration, medication and liver condition all influence that time. What does not change is the mechanism: the only reliable method is time. Coffee, cold showers, exercise and remedies accelerate nothing — they merely mask the symptoms. This is why anyone who drank in the evening should seriously consider that they may still be over the limit the next morning.

The liver processes almost all the alcohol you drink, and it is also the organ that suffers most from regular consumption. The process generates toxic by-products that inflame and damage liver cells. The first stage is usually fatty liver disease — a build-up of fat in the organ — which is reversible if drinking stops.

If consumption continues, the condition can progress to alcoholic hepatitis and later to cirrhosis, which is irreversible and permanently impairs liver function. Risk does not depend on quantity alone: frequency, genetic predisposition, sex and the presence of viral hepatitis all matter. Symptoms tend to appear late, once damage is already advanced — which makes cutting back the single most effective step.

The WHO recommended alcohol dose has shifted in tone in recent years. For a long time the guidance was framed as moderation — up to one drink a day for women and two for men, based on a standard drink of 10 g of pure alcohol. That reference still appears in a lot of material, but it is no longer presented as a safety recommendation.

The World Health Organization's current position is blunter: there is no safe level of alcohol consumption. Alcohol is classified as a Group 1 carcinogen, the same category as tobacco and asbestos, and cancer risk begins to rise from the first drinks. In a driving context the guidance is simpler still and admits no middle ground: if you are driving, the recommended amount is zero.

Alcohol is a central nervous system depressant and it degrades driving long before someone feels drunk. Even at low levels you get slower reflexes, difficulty judging distance and speed, narrowed peripheral vision and a longer reaction time — precisely the capacities driving depends on.

The most dangerous effect is behavioural: alcohol lowers your perception of risk while raising your confidence. The driver feels more capable exactly as they become objectively less capable, and that combination explains why so many people judge themselves fit to drive when they are not. At higher levels, loss of motor coordination, drowsiness and double vision are added. Self-assessment is therefore useless as a test — the only reliable reference is not having drunk at all.

In the short term alcohol can feel relaxing, because it depresses the central nervous system and briefly reduces anxiety. That relief is short-lived and comes at a cost: as the level falls, the body enters a rebound effect that usually increases anxiety and worsens mood over the following hours.

Alcohol also degrades sleep quality, particularly deep sleep, leaving you more tired and less able to tolerate stress the next day. Using drink as a recurring strategy for pressure or insomnia is one of the most common routes into dependence, because tolerance builds and the dose needed grows. Approaches with actual evidence behind them — physical activity, regular sleep, professional support — work better and do not create that cycle.

Some signs are well established: difficulty controlling how much you drink once you start, needing steadily larger amounts for the same effect, drinking in the morning or to relieve withdrawal symptoms, and continuing to drink despite clear damage to work, health or relationships.

Other signs are quieter: hiding how much you drink, becoming irritated when someone raises the subject, planning your day around drinking, or trying repeatedly to stop without success. You do not need to tick every box to seek help — two or three is reason enough to talk to a health professional. In Brazil, treatment is available free through the public health system (SUS), including CAPS AD centres that specialise in alcohol and other drugs.