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Japan

Blood Alcohol Content Calculator – Japan Drink Driving Limit 🇯🇵

Driving in Japan? The legal threshold for 酒気帯び (alcohol-affected) driving is 0.15 mg of alcohol per litre of breath — about 0.03% blood alcohol. Our BAC calculator estimates your blood alcohol content and when you'll be under the limit again. Since November 2024, the same 0.15 mg/L limit also applies to cycling.

0.15 mg/L Drink-drive limit

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Alcohol Limit Japan: 0.15mg/L Breath (酒気帯び) — Plus 酒酔い With No Number — 0.15 mg/L

Japan's drink-driving threshold is 0.15 mg/L of breath (about 0.03% blood alcohol). 0.15–0.25 mg/L means 13 demerit points and a 90-day suspension; 0.25 mg/L or more means 25 points and licence revocation (2-year disqualification). If alcohol leaves you unable to drive normally, it is treated as 酒酔い (drunk driving) regardless of the number — 35 points, revocation (3-year disqualification), and up to 5 years in prison or a ¥1,000,000 fine.

🚲 Bicycles count too: since the November 2024 law change, riding a bicycle while alcohol-affected is also punishable. Check that the alcohol has cleared with this calculator before you ride, not just before you drive.

ℹ️ Information

CONTEXT
🌎 Country
Show results in
ABOUT YOU
Sex
⚖️ Weight

lbs

⏱️ Start time of drinking (optional) Time of your first drink (not required)

🕒

⏳ Or: hours ago —
0h6h12h18h24h

🍹🍸🍺 Drinks

Drink {{ index+1 }}

{{ drinkSummary(drink) }}

%

≈ {{ servingHint(drink) }}

Maximum number of drinks reached.

The results will show up here...
📈 Results
Current BACPeak BAC {{ initialSobriety }}{{ unitSign }} Drink-drive limit {{ countryLimit }}{{ unitSign }}
Safe Caution Impaired Intoxicated Dangerous
Above the Japanese limit. Close to the 0.15 mg/L Japanese limit — this estimate could already be over. Below the 0.15 mg/L Japanese limit.
Time until {{ impactLimitLabel }}: {{ legalLimitTimeLabel }}
Time until {{ zeroTargetLabel }}: {{ sobrietyDuration }}

Alcohol Limit Japan: 0.15mg/L Breath (酒気帯び) — Plus 酒酔い With No Number

Alcohol-affected (breath 0.15–0.25 mg/L) 0.15 mg/L
Alcohol-affected 0.25 mg/L+ / drunk driving 0.25 mg/L

Japan Drink Driving Penalties, Demerit Points & Fines

Offence type No offence Below the legal limit – driving is permitted.
Offence type Over the 0.0 limit Zero-tolerance country — driving with any detectable alcohol is prohibited.
Offence type Over the legal limit You are over the legal limit and committing a drink-driving offence. Exact penalties depend on your BAC and local law.
Offence type Alcohol-affected driving (酒気帯び) Alcohol-affected (0.15 mg/L+) Criminal offence — licence suspension or revocation plus imprisonment or a fine.
Typical penalties
  • 13–25 demerit points
  • 90-day suspension to revocation (2-yr disqualification)
  • Up to 3 years prison or ¥500,000 fine
Offence type Drunk driving (酒酔い) Drunk driving / causing injury Criminal offence — may result in a criminal record.
Typical penalties
  • 35 demerit points, licence revoked (3-yr disqualification)
  • Up to 5 years prison or ¥1,000,000 fine
  • Far longer where death or injury results
These are general penalties. Actual consequences may vary by local law and circumstances. Learn more →

Drink-drive limit

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Based on Japanese law (0.15 mg/L breath ≈ 0.03%) ·

Elimination rate

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Typical average

Standard Drinks

{{ standardDrinks }}🍺
Approx. consumed

Pure Alcohol

{{ results.length > 0 ? results[0].pureAlcoholMl : '0' }} {{ qunits }}
Pure alcohol consumed

Pure Alcohol (g)

{{ alcoholGrams }} g
Total ethanol consumed

Calories

{{ calories }} kcal
From alcohol only — mixers add more

Time over limit

{{ timeOverLimit || '0m' }}
Estimated duration above the 0.15 mg/L Japanese limit
For your own safety, we recommend using a rate no higher than the average.
Current BACPeak BAC {{ initialSobriety }}{{ unitSign }} Drink-drive limit {{ countryLimit }}{{ unitSign }}
Safe Caution Impaired Intoxicated Dangerous
Above the Japanese limit. Close to the 0.15 mg/L Japanese limit — this estimate could already be over. Below the 0.15 mg/L Japanese limit.
Time until {{ impactLimitLabel }}: {{ legalLimitTimeLabel }}
Time until {{ zeroTargetLabel }}: {{ sobrietyDuration }}

Alcohol Limit Japan: 0.15mg/L Breath (酒気帯び) — Plus 酒酔い With No Number

Alcohol-affected (breath 0.15–0.25 mg/L) 0.15 mg/L
Alcohol-affected 0.25 mg/L+ / drunk driving 0.25 mg/L

Japan Drink Driving Penalties, Demerit Points & Fines

Offence type No offence Below the legal limit – driving is permitted.
Offence type Over the 0.0 limit Zero-tolerance country — driving with any detectable alcohol is prohibited.
Offence type Over the legal limit You are over the legal limit and committing a drink-driving offence. Exact penalties depend on your BAC and local law.
Offence type Alcohol-affected driving (酒気帯び) Alcohol-affected (0.15 mg/L+) Criminal offence — licence suspension or revocation plus imprisonment or a fine.
Typical penalties
  • 13–25 demerit points
  • 90-day suspension to revocation (2-yr disqualification)
  • Up to 3 years prison or ¥500,000 fine
Offence type Drunk driving (酒酔い) Drunk driving / causing injury Criminal offence — may result in a criminal record.
Typical penalties
  • 35 demerit points, licence revoked (3-yr disqualification)
  • Up to 5 years prison or ¥1,000,000 fine
  • Far longer where death or injury results
These are general penalties. Actual consequences may vary by local law and circumstances. Learn more →
{{ afterLabel }} {{ $t('unit.' + units) }} Status
{{ result.time }} {{ result.drunkenness }}
  • Below the 0.15 mg/L Japanese limit.
  • Close to the 0.15 mg/L Japanese limit — this estimate could already be over.
  • Above the Japanese limit.

This is general information, not legal advice, and the estimate is approximate. The only safe level before driving is zero.

Create a pop-up notification

Sobriety Over Time

Your estimated BAC as your body clears the alcohol

Time until {{ zeroTargetLabel }} {{ sobrietyDuration }}
  • {{ lookaheadBacDisplay }}{{ unitSign }} Above the Japanese limit. Close to the 0.15 mg/L Japanese limit — this estimate could already be over. Below the 0.15 mg/L Japanese limit.
  • {{ $t('unit.' + units) }}
  • Drink-drive limit ({{ countryLimit }}{{ unitSign }})
👮 Health impact and legal consequences
{{ item.title }} {{ item.summary }} {{ $t('severity.' + item.severity) }}

{{ $t('impact.limit_note', { limit: impactLimitLabel }) }}

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Peak BAC: {{ peakBAC }}

💡 Advice: drink water, eat, and avoid driving. Japan's threshold is just 0.15 mg/L of breath (≈0.03%). If you are anywhere near it, find another way home.

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Attention‼️ The results are only approximate, so make sure you are sober before driving.

About results
Current BAC

Your Current BAC is the estimated alcohol in your body, shown here in mg/L of breath, promille (‰) or as a percentage. Japanese police test breath, and the key threshold — 0.15 mg/L — is roughly 0.03% blood alcohol.

Legal limit

Driving at 0.15 mg/L of breath or above is an offence: 0.15–0.25 mg/L brings 13 demerit points and a 90-day suspension, and 0.25 mg/L or more brings 25 points and revocation. If drink leaves you unable to drive normally it is 酒酔い (drunk driving) at any reading — 35 points, revocation and up to five years’ prison or a ¥1,000,000 fine. Since November 2024 the same rules reach cyclists, so check the alcohol has cleared before you ride, not just before you drive.

Elimination rate

Alcohol leaves the body at a roughly fixed pace — about 0.15 ‰ (0.015%) an hour — and nothing hurries it. A coffee, a hot bath or a meal change how you feel while the reading falls no faster, which is why you can still be over the line the next morning.

Standard Drinks

Japan counts a standard drink as about 20 g of pure alcohol — one 500 ml can of 5% beer, or roughly a 180 ml cup (一合) of 15% sake. Spirits and chūhai vary widely, so this total converts whatever you drank into comparable units.

Pure Alcohol

The total pure alcohol (ethanol) your body has absorbed, in grams — the figure behind your standard-drink count and your BAC.

Time vs. Sobriety Table

The table projects your BAC each hour, and with your first-drink time it maps them onto the clock — useful the morning after, showing when you fall back under 0.15 mg/L. Status icons mark the hours it is safe to drive or ride.

Sobriety Over Time Graph

A line chart of your BAC falling over the hours ahead, showing when it drops below the legal threshold and then to zero.

How Alcohol Affects You

A reference table matching BAC ranges to their usual effects on judgement, coordination and reaction time — impairment that begins well below any legal figure.

Legal limit reached in / Sober in / Peak BAC

Quick summary estimates:

  • Legal limit reached in: time until your BAC falls below 0.15 mg/L of breath.

  • Sober in: time until it returns to ~0.

  • Peak BAC: the highest level reached in the session.

Japan Drink Driving Limit & Alcohol Calculator Data

Five factors that determine your result

Weight
Body weight determines how alcohol distributes in the body — more weight means a lower blood alcohol concentration.
Sex
Men and women metabolise alcohol at different rates because of differences in body water content.
Amount
The amount of pure alcohol consumed is the main factor that determines your BAC result.
Strength
A higher strength (%) means more ethanol in the same drink serving.
Time
The time of your first drink shows how BAC changes hour by hour and when you'll be sober again.

How much does Japan drink?

Alcohol consumption per adult, per year

6.3L

litres of pure alcohol per adult (15+), per year

Per adult, that is roughly:

252 beers ≈ 5/week
350 glasses of wine ≈ 7/week
394 shots ≈ 8/week
6.3 L
0.1 L Ø 4.2 11.2 L

51% above the regional average

Ranks #7 of 25 in Western Pacific Ranks #71 of 188 in the World Average in Western Pacific: 4.2 L

How neighbours compare

#1 Russia 10.5L #22 Europe
#2 Japan 6.3L #7 Western Pacific
#3 China 4.5L #10 Western Pacific
#4 Singapore 2.0L #15 Western Pacific

How safe are the roads in Japan?

Road traffic deaths per 100,000 people, per year

2.7 /100k

road traffic deaths per 100,000 people, 2021

~36% of road deaths linked to alcohol WHO estimate, 2019 · 25–51%
64 road deaths per week WHO estimate, 2021
23 alcohol-linked deaths per week WHO-derived estimate
2.7
0.0 Ø 10.8 22.2

75% fewer road deaths than the regional average

#3 safest of 28 in Western Pacific #13 safest of 195 worldwide Average in Western Pacific: 10.8 per 100k

How neighbours compare

#1 Singapore 1.9 #2 Western Pacific
#2 Japan 2.7 #3 Western Pacific
#3 Russia 10.6 #45 Europe
#4 China 17.4 #23 Western Pacific

Latest available year shown per country.

LIMITS NEARBY

BAC limits in neighboring countries

Explore the legal blood alcohol concentration (BAC) limits for drivers in nearby countries.

KR

South Korea

0.15mg/L
Strict
CN

China

0.1mg/L
Strict
TW

Taiwan

0.25mg/L
Moderate
RU

Russia

0.15mg/L
Strict
SG

Singapore

0.4mg/L
Relaxed

Alcohol Limit Japan: 0.15mg/L Breath (酒気帯び) — Plus 酒酔い With No Number

Drink driving thresholds for Japan (酒気帯び / 酒酔い)

Alcohol-affected (breath 0.15–0.25 mg/L)
0.15mg/L
Moderate
Alcohol-affected 0.25 mg/L+ / drunk driving
0.25mg/L
Strict
Japan's drink-driving threshold is 0.15 mg/L of breath (about 0.03% blood alcohol). 0.15–0.25 mg/L means 13 demerit points and a 90-day suspension; 0.25 mg/L or more means 25 points and licence revocation (2-year disqualification). If alcohol leaves you unable to drive normally, it is treated as 酒酔い (drunk driving) regardless of the number — 35 points, revocation (3-year disqualification), and up to 5 years in prison or a ¥1,000,000 fine.

🚲 Bicycles count too: since the November 2024 law change, riding a bicycle while alcohol-affected is also punishable. Check that the alcohol has cleared with this calculator before you ride, not just before you drive.
Verified with official source
Legal limits checked against laws.e-gov.go.jp
Last verified: 2026-09-13
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Japan Drink Driving Penalties, Demerit Points & Fines

Consequences of drink driving in Japan by severity

Alcohol-affected (0.15 mg/L+)
Alcohol-affected driving (酒気帯び)
  • 13–25 demerit points
  • 90-day suspension to revocation (2-yr disqualification)
  • Up to 3 years prison or ¥500,000 fine
Drunk driving / causing injury
Drunk driving (酒酔い)
  • 35 demerit points, licence revoked (3-yr disqualification)
  • Up to 5 years prison or ¥1,000,000 fine
  • Far longer where death or injury results

Source: Road Traffic Act (道路交通法); National Police Agency (警察庁). Penalties vary by case.

Responsible Drinking & Japan's 0.15mg/L Limit

Practical tips for safer drinking

Pace yourself
Stick to the "one drink per hour" rule – your liver needs time to process alcohol.
Eat before and while drinking
A solid meal slows alcohol absorption – an empty stomach raises BAC faster.
Drink water
After each alcoholic drink, have a glass of water – it reduces dehydration and health risks.
Don't drive
Japan's threshold is just 0.15 mg/L of breath. Use a taxi, a 代行 (daikō) service, or stay overnight.

Source: WHO; Japan Ministry of Health, Labour and Welfare (MHLW); Road Traffic Act.

Official sources & references

The limits and penalties on this page come from official government sources

Confirm the current rules directly with the responsible authorities:

Laws change — always check the latest limits and penalties with the official source before driving.

How we calculate your BAC

The exact formula, step by step

Your result is not a guess. It comes from the Widmark equation, the same formula forensic toxicologists use in court. Here it is, worked through with an example.

BAC = A ÷ (r × W) − (β × t)

where A = grams of pure alcohol, r = body-water factor (0.68 for men, 0.55 for women), W = weight in kg, β = elimination rate (~0.15 g/L per hour), and t = hours since your first drink.

  1. Pure alcohol (A). Three 500 ml beers at 5% ABV hold 3 × 500 × 0.05 × 0.789 ≈ 59 g of pure alcohol.
  2. Body water (r × W). For an 80 kg man: 0.68 × 80 = 54.4.
  3. Peak level. A ÷ (r × W) = 59 ÷ 54.4 ≈ 1.09 g/L — the same as 1.09‰ or about 0.11% BAC.
  4. Subtract elimination. After 2 hours: 1.09 − (0.15 × 2) = 0.79 g/L.

The calculator runs this same equation on your own weight, sex, drinks and timing — the numbers above are only a worked example. Method based on E. M. P. Widmark (1932); results are an estimate, not a legal measurement.

What people actually log

SmartBAC has run over 17,000 calculations in recent weeks. Of every drink people log, beer is the most common by far — about 6 in 10 — ahead of spirits and then wine.

Anonymous, aggregated first-party usage data from SmartBAC, July–August 2026.

FAQ

How long does alcohol stay in your blood?

Your body removes alcohol at a fairly steady rate — roughly 0.15 ‰ per hour, or about 7g of pure alcohol an hour. Starting from a BAC of 1.0 ‰, it would take about 7–10 hours to clear completely; from 1.5 ‰, more like 12 hours. From a single beer at around 0.3 ‰, allow roughly 3–4 hours to reach zero.

That figure is an estimate, not a guarantee. The actual time depends on your weight, sex, metabolism, whether you have eaten, and your general health, so two people who reach the same BAC can sober up at different speeds. Detection windows differ from "safe to drive" windows — what matters for driving in Japan is whether your blood concentration is back under the legal limit, and ideally at zero.

How can I sober up faster?

The honest answer is that you cannot sober up faster. Your liver breaks down alcohol at an essentially fixed rate, and only time lowers your blood alcohol content. Popular "remedies" — black coffee, a cold shower, fresh air, exercise, a big meal after drinking, or being sick — do not change how quickly alcohol leaves your system.

What some of these can do is make you feel more alert, and that is precisely the danger: feeling more awake while your BAC is still above the limit can fool you into thinking you are fit to drive when you are not. Coffee, for example, masks tiredness without touching your alcohol level. Drinking water is sensible for rehydration and may ease a hangover, but it does not speed up sobering up. The only safe plan is to wait until your BAC is genuinely back down — or simply not drive that day.

How accurate are Japanese police breathalysers?

Japanese police use certified, regularly calibrated breath alcohol detectors, which gives their readings legal weight in court. The devices carry a small built-in margin of error, and that tolerance is already factored into how they are certified for evidential use. Alcohol lingering in the mouth (from a recent drink or mouthwash) can briefly raise readings, so officers normally allow a short wait before testing.

Consumer-grade personal alcohol checkers are less accurate than police equipment, lose calibration over time, and have no legal standing. They can be useful for awareness — particularly the morning after — but should never be your green light to drive. Online calculators don't measure anything; they model your BAC from the inputs you provide, so if your details are off, the estimate is off too.

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