# BAC and standard drinks, explained

> Blood alcohol made simple for Smart Serve: what a standard drink is in Canada, what raises BAC, Ontario’s 0.05 and 0.08 limits, and how to count drinks.

Canonical: https://smartservepracticetest.ca/bac-chart
Last updated: 2026-10-26

Smart Serve expects you to understand **standard drinks** and what affects **blood alcohol concentration (BAC)**. You don’t need to calculate anyone’s BAC at work, and you can’t. You do need to know how much alcohol is in what you pour, and why two guests can react very differently to the same drinks.

## What one standard drink is

In Canada, one standard drink contains **17.05 mL (13.45 g) of pure alcohol**. Each of these is one standard drink:

*Health Canada / Canada’s Guidance on Alcohol and Health.*
| Drink | Size | Alcohol |
| --- | --- | --- |
| Beer, cider or cooler | 341 mL (12 oz) | 5% |
| Wine | 142 mL (5 oz) | 12% |
| Spirits | 43 mL (1.5 oz) | 40% |

### Counting drinks that aren’t standard

Multiply the volume by the alcohol percentage, then divide by 17.05 mL. Some worked examples:

*Our arithmetic from the standard drink definition.*
| What you pour | Pure alcohol | Standard drinks |
| --- | --- | --- |
| 473 mL tall can, 5% | 473 × 0.05 = 23.7 mL | About 1.4 |
| 341 mL craft beer, 10% | 341 × 0.10 = 34.1 mL | About 2 |
| 86 mL double, 40% spirits | 86 × 0.40 = 34.4 mL | About 2 |
| 250 mL glass of wine, 12% | 250 × 0.12 = 30 mL | About 1.8 |

> Don’t mix this up with the **standard serving sizes** in Ontario’s minimum-price rule (O. Reg. 746/21, s. 26): 341 mL beer, 142 mL wine, 85 mL fortified wine and **29 mL (1 oz) spirits**. Those set the lowest legal price per serving. They aren’t the health definition of a standard drink.

## What affects BAC

Smart Serve’s BAC chart lists the factors that change how alcohol affects a person:

- **Body size and body fat:** the same drinks raise BAC more in a smaller body.
- **Food:** food slows the absorption of alcohol. The AGCO also notes it tends to slow the pace of drinking.
- **Medications and other drugs,** including cannabis: they can add to the effects.
- **Metabolism, health, hydration, fitness and age.**
- **Time:** Smart Serve’s chart assumes the body clears roughly **one standard drink an hour**, and says real rates vary from person to person.

That’s why you watch the **guest**, not the count. Smart Serve says its chart is for education only and shouldn’t be the only basis for judging whether someone is intoxicated or able to drive.

## Ontario’s driving limits

*Ontario.ca, Impaired driving. Penalties changed on July 1, 2026; check ontario.ca for current amounts.*
| BAC | What it means in Ontario |
| --- | --- |
| Any alcohol | Not allowed for drivers 21 and under, G1, G2, M1 and M2 drivers, and certain commercial drivers (zero tolerance) |
| 0.05 to 0.079 | The “warn range”: immediate licence suspensions and penalties |
| 0.08 or more | A criminal offence, with an immediate 90-day suspension |

Drug-impaired driving, including cannabis or a mix of drugs and alcohol, carries the same penalties as alcohol-impaired driving.

## Health guidance worth knowing

Canada’s Guidance on Alcohol and Health (2023) describes risk by drinks per week: **1–2 low**, **3–6 moderate** and **7 or more increasingly high**. Ontario also requires every licensed establishment to post a sign warning that drinking during pregnancy can harm a baby.

## Questions people ask

### What is the Smart Serve BAC chart?

It’s an educational tool on smartserve.ca that estimates BAC by sex, weight, number of standard drinks and time. Smart Serve says it’s for demonstration only and shouldn’t be used to decide whether someone can drive.

### How many standard drinks are in a tall can of beer?

A 473 mL can at 5% holds about 23.7 mL of pure alcohol, about 1.4 standard drinks.

### Is a 1 oz shot a standard drink?

Not by the health definition. A standard drink of 40% spirits is 43 mL (1.5 oz). Ontario’s minimum-price rule uses 29 mL (1 oz) as its standard spirits serving, which is a pricing rule, not a health measure.

### What is the legal BAC limit in Ontario?

0.08 is the criminal limit. From 0.05 to 0.079 is Ontario’s warn range with immediate suspensions. Drivers 21 and under and novice drivers must have zero alcohol.

## Sources

- [Health Canada: Low-risk alcohol drinking guidelines (standard drink)](https://www.canada.ca/en/health-canada/services/substance-use/alcohol/low-risk-alcohol-drinking-guidelines.html) (checked 2026-10-26)
- [CCSA: Canada’s Guidance on Alcohol and Health, final report (2023)](https://www.ccsa.ca/sites/default/files/2023-01/Canada's%20Guidance%20on%20Alcohol%20and%20Health%20Final%20Report_l.pdf) (checked 2026-10-26)
- [Smart Serve Ontario: BAC Chart](https://smartserve.ca/bac-chart/) (checked 2026-10-26)
- [Ontario.ca: Impaired driving](https://www.ontario.ca/page/impaired-driving) (checked 2026-10-26)
- [O. Reg. 746/21: Licensing (e-Laws)](https://www.ontario.ca/laws/regulation/r21746) (checked 2026-10-26)
- [O. Reg. 745/21: General (e-Laws)](https://www.ontario.ca/laws/regulation/r21745) (checked 2026-10-26)
- [AGCO: Information sheet, recognizing intoxication](https://www.agco.ca/en/alcohol/information-sheet-recognizing-intoxication) (checked 2026-10-26)

Not affiliated with Smart Serve Ontario or the Alcohol and Gaming Commission of Ontario (AGCO).

## Related

- [Signs of intoxication](https://smartservepracticetest.ca/signs-of-intoxication)
- [Intoxication and refusing service: practice quiz](https://smartservepracticetest.ca/practice/intoxication)
- [Smart Serve practice test](https://smartservepracticetest.ca/smart-serve-practice-test)
- [The Smart Serve test: what to expect](https://smartservepracticetest.ca/smart-serve-test)