Tagespegel – Blood Alcohol Calculator

Food mainly affects how fast and how high your level rises. Fatty, protein-rich meals keep the alcohol in the stomach longer before it reaches the small intestine, where most of it passes into the blood. Absorption is stretched out, so the peak comes out lower and later.

Food also affects the effective amount: on a full stomach a larger share of the alcohol is broken down in the stomach and liver before it ever reaches the blood – the so-called resorption deficit. The more you've eaten, the bigger this reduction. Whatever does reach the blood still has to be broken down fully in the end, and that takes time.

That's why the body-data section has an “Eaten?” field. Depending on your choice (nothing, some, a lot) the calculator uses a longer absorption time and a larger resorption deficit. The solid line – and thus the “now” value and the gauge – stays deliberately cautious: full alcohol amount, mean elimination of 0.15 ‰ per hour. The shaded area around it shows a plausible range: upper edge with the full peak and slow elimination (0.1 ‰/h), lower edge with a resorption deficit (10–30 % depending on stomach contents) and fast elimination (0.2 ‰/h). A rough guide, not an exact confidence interval.

By default this calculator uses the classic Widmark model: the grams of pure alcohol are divided by body weight times a fixed distribution factor (around 0.68 for men, 0.55 for women). This is simple, established for almost a century and recognised in court. But the fixed factor only knows weight and sex – two people of the same weight with a very different build get the same value, even though their body-water percentage differs.

If you optionally enter your height under “Body data”, you can switch to the refined Seidl model. It keeps the basic Widmark formula but calculates the distribution factor from weight and height instead of a fixed number. In drinking experiments the values calculated this way matched actually measured blood levels considerably better than the rigid factor.

The Watson model goes one step further: from height, weight and (for men) age it first estimates total body water and derives the distribution factor from it. Physiologically this is the most individualised approach and is considered the preferred basis for estimating body water in the forensic literature. Important: all three models change only the distribution factor – absorption and elimination (around 0.15 ‰ per hour) stay the same, and all remain an estimate, not a measurement. Without extra input, classic Widmark stays active.

For pure blood alcohol level: your liver doesn't care about the order in which the alcohol arrived. What matters is the total amount of pure alcohol, your body weight and time – exactly the quantities this calculator works with. Whether beer first then wine or the other way round: with the same amount of alcohol you end up at the same BAC.

The saying persists anyway, and it has a psychological kernel. Someone who starts with light beer and later switches to high-proof wine or spirits often unnoticeably drinks more alcohol faster – the level climbs more steeply than it feels. So switching “upwards” encourages overdoing it, not the order itself.

A controlled study by the University of Witten/Herdecke and the University of Cambridge (2019) found no evidence that the order affects the hangover – neither the type nor the order of drinks changed hangover severity significantly. In short: the hangover comes from the amount, not the choreography. “Beer before wine” is more a memory aid for moderation than a biological truth.

The warming feeling after a digestif is real, but the mechanism behind it is different than thought. Alcohol tends to slow gastric emptying rather than speed it up. So heavy, rich food actually stays in the stomach longer – the shot merely masks the feeling of fullness because alcohol dulls perception and relaxes the muscles.

What many experience as a “digestive aid” is mainly the bitter herbal content of many digestifs: bitter compounds can stimulate the flow of saliva and gastric juices. But you don't need alcohol for that – a bitter tea or an alcohol-free herbal extract does the same without raising your level.

For your alcohol level the shot counts as normal: 2 cl at 40 % is around 6 grams of pure alcohol. As a cosy end to a meal there's little to object to – you just “digest” despite it rather than because of it.

Unfortunately no. The body eliminates alcohol at a largely fixed rate – around 0.1 to 0.2 ‰ per hour (about 0.15 on average), regardless of what else you do. This breakdown happens almost entirely via the liver and cannot be sped up noticeably by coffee, cold showers, fresh air, exercise or vomiting.

Coffee and other stimulants do exactly that: they make you alert. That's actually treacherous, because caffeine masks tiredness without removing the impairment of reaction, judgement and coordination. You feel fitter than you are – dangerous above all behind the wheel.

The only thing that really helps is time. That's exactly what the “sober from” estimate in this calculator shows you: a rough forecast of when your level is calculated to be back at 0.0 ‰. The calculator uses the mean elimination rate of 0.15 ‰ per hour; the shaded area in the chart shows the possible range of 0.1 to 0.2 ‰ per hour. Until then no trick helps – only waiting.

There's something to the saying on average, but the explanation is more biological than cultural. Alcohol is distributed in body water, and muscle tissue holds considerably more water than fatty tissue. Because the female body has a somewhat higher fat percentage on statistical average, the same amount of alcohol is distributed across less body water – so the BAC comes out higher.

That's exactly what the so-called Widmark distribution factor reflects: this calculator uses around 0.68 for men and 0.55 for women. With the same weight and the same amount consumed, women therefore end up with a higher calculated level. On top of that, women have on average slightly less of the alcohol-degrading enzyme alcohol dehydrogenase in the stomach.

The important word is “average”: a muscular, light man can have a worse value than a sturdy woman. The factor is an approximation for the population average, not an individual measurement – your personal daily condition can differ considerably.

Falling asleep yes, sleeping well no. Alcohol has a sedative effect and often shortens the time it takes to fall asleep – hence the feeling that it helps. But as soon as the body starts breaking it down, the effect flips: the second half of the night becomes more restless, with more frequent waking and shallower sleep.

REM sleep – the dream phase important for recovery and memory – suffers in particular. Alcohol suppresses it at first, and later the body “catches up” in fragments – the result is vivid dreams, sweating and the familiar waking at four in the morning. The relaxing effect on the throat muscles also increases snoring and breathing pauses.

The bottom line: after a nightcap you fall asleep faster but sleep worse through the night – and wake up less rested. As a sleep aid, alcohol is therefore a bad deal that additionally fuels the next morning's hangover.

The price is the wrong trail. The main cause of a hangover is simply the amount of alcohol plus its effect as a cell toxin and diuretic – and that's chemically identical in expensive and cheap drinks. Whoever drinks a lot gets a hangover, no matter what's on the label.

There is a small true kernel with the so-called congeners (fusel alcohols and flavour compounds). Dark spirits like whisky, cognac or red wine contain more of them than clear ones like vodka or gin, and these substances are suspected of intensifying the hangover. But the congener content has little to do with price – an expensive whisky can contain more of them than a cheap vodka.

What often softens the hangover with premium drinks is drinking behaviour: you sip good wine more slowly and in smaller amounts than cheap sparkling wine at a party. So it's not the price that saves you, but the pace and quantity.

Habituation mainly changes how the alcohol feels – not how much is in the blood. Regular drinkers develop a tolerance: the brain reacts less sensitively, so you seem and feel less drunk at the same level. But the BAC itself is exactly the same as for an inexperienced drinker.

That's the real danger of this “tolerance”: you underestimate your own state. At a traffic check only the measured value counts, not the subjective feeling of sobriety. Someone at 1.3 ‰ who feels fine is nonetheless in the criminally relevant range.

In the long term a high tolerance is also a warning sign, not a compliment: it shows the body has adapted to regular consumption and often goes hand in hand with rising amounts. This calculator knows nothing of habituation – it shows you the sober numerical value, regardless of how “safe” you feel.

The notorious alcohol breath hardly arises in the mouth, but in the lungs. As soon as alcohol circulates in the blood, some of it passes into the breath via the alveoli – so you can be smelled as long as measurable alcohol is in the blood. Alcohol breath is therefore not superficial bad breath but a direct reflection of your level, which is why the smell remains even after brushing your teeth.

As a rough rule of thumb: as long as your level is above zero, you can potentially be smelled – and because the body eliminates only slowly, that can last many hours, after a boozy night well into the next morning. The typical “morning after” smell is exactly this residual alcohol still being broken down. Alcohol also causes a drier mouth and encourages odour-forming bacteria, which amplifies the effect.

Against the actual alcohol breath, neither chewing gum nor coffee nor mouthwash helps – at best they cover the smell briefly while alcohol keeps coming from the lungs. The only thing that really makes the smell disappear is the same factor as with the level: time. When the smell is gone, that roughly means the alcohol is largely broken down too – but you can't read a blood value from it.

For your blood alcohol level the answer is short: a natural wine has 12 to 13 percent just like any other wine. The label says nothing about the amount of pure alcohol in the glass – and that is exactly what this calculator works with. Half a litre of natural wine lands you at the same reading as a conventional wine of the same strength.

For the hangover, too, the amount of alcohol is by far the most important factor. Congeners – trace compounds such as fusel oils, tannins or acetaldehyde – play a measurable but small role. In a controlled study bourbon, which contains many times more congeners, produced a worse hangover than vodka; the effect of the ethanol itself was considerably stronger. Between two wines that difference is small anyway.

That leaves the sulfites and their bad reputation. There is no evidence linking sulfites to hangovers. Genuine sulfite sensitivity affects a small group and shows up as an asthmatic reaction, not as a headache the next morning. For comparison: dried fruit such as apricots or raisins contains many times the sulfites of a glass of wine.

“Natural wine” is therefore a statement about how the wine was made, not about how well you will tolerate it. Enter it like any other wine, with volume and percentage – the calculator does not read labels, and as far as your blood alcohol level goes, neither does your body.

Essentially not – but “alcohol-free” does not mean “without alcohol”. In Germany a beer may be sold as alcohol-free if it contains at most 0.5 % ABV. Only beers explicitly labelled “0.0 %” are genuinely close to zero: those stay below 0.05 % ABV, less than a tenth as much.

The Institute of Forensic Medicine at the University of Freiburg measured what that means in the blood. Participants drank 1.5 litres of alcohol-free beer at 0.41 to 0.42 % ABV within one hour. Across 67 usable data sets, alcohol was detectable in only 20 people – the highest reading was 0.0056 ‰. The lowest zone of this calculator starts at 0.3 ‰, more than fifty times that.

You can follow the arithmetic here. 1.5 litres at the legal maximum of 0.5 % ABV is roughly 5.9 grams of pure alcohol. For a 75 kg person that would be a little over 0.1 ‰ by the Widmark formula – if it all entered the bloodstream at once. In reality the intake spreads over the time spent drinking, while the body eliminates around 0.15 ‰ per hour. Elimination outpaces intake, so nothing accumulates.

Two caveats. For anyone staying sober because of alcohol dependence, the residual alcohol – and even more so the familiar taste – can be a problem; “0.0 %” is the clearer choice there. And drinking very large amounts in a short time may not register on the gauge, but your stomach will notice.