Alcohol Units Calculator
UK units and grams of alcohol from drinks, size, and ABV.
What it does
Alcohol hides in volume times strength, which units expose: milliliters times ABV divided by a thousand. A 330 ml beer at five percent holds 1.65 units, while a large wine glass holds three, though both feel like one drink.
The tool above takes drink count, size, and strength. It returns UK units, grams of pure alcohol, and the share of the fourteen unit weekly low-risk guide.
Fourteen units a week spread over three plus days with alcohol free days is the UK low-risk line for both sexes. Binge episodes break the pattern even inside weekly totals, since peak blood alcohol drives acute harm.
US standard drinks run near fourteen grams against eight gram UK units, so American drink counts read almost double in units. Travelers comparing guidance must convert, not transplant.
How to use
- Enter how many of the same drink.
- Enter size in ml from the label or glass.
- Enter ABV percent from the label.
- Spread weekly units across days with free days.
Formula
- ml x ABV
- Pure alcohol milliliters in the drink.
- / 1000
- Scales to UK units of 10 ml alcohol each.
- x 8
- Grams per unit at 0.789 density.
Density 0.789 g per ml turns 10 ml of alcohol into 7.9 grams, rounded to 8 per unit. US standard drinks hold 14 grams, near 1.75 UK units.
Worked example
Example: two 330 ml beers at 5%
Two bottles, 330 ml each, 5% ABV.
- Units: 2 x 330 x 5 / 1000 = 3.3 units.
- Grams: 3.3 x 8 = 26.4, shown as 26 g.
- Share: 3.3 / 14 = 23.6% of the weekly guide.
- Same volume at 0.5% light beer is 0.33 units.
Reference table
| Drink | Math | Units |
|---|---|---|
| 330 ml beer 5% | 330x5/1000 | 1.65 |
| 568 ml pint 4% | 568x4/1000 | 2.27 |
| 175 ml wine 13% | 175x13/1000 | 2.27 |
| 25 ml spirit 40% | 25x40/1000 | 1 |
| 750 ml wine 13% | 750x13/1000 | 9.75 |
Limits
- Labels assumed exact. Pours vary wildly at home.
- Guide is population low risk, not personal safe.
- Pregnancy guidance is zero, not fourteen.
- Medicines and conditions lower tolerance a lot.
Common mistakes
- Counting glasses instead of units.
- Free pouring spirits at double measures.
- Saving the week for one binge night.
- Comparing US drinks one to one with units.
- Trusting light labels without reading ABV.
Try it yourself
Quick checks. Answers sit tucked under each question.
One pint 568 ml at 5%?
568 x 5 / 1000 = 2.84 units.
Three 175 ml glasses at 12%?
3 x 175 x 12 / 1000 = 6.3 units.
Questions
What is a unit of alcohol?
Ten ml of pure alcohol: ml times ABV divided by 1000.
How many units a week is low risk?
Fourteen spread over three plus days with alcohol free days, per UK guidance.
How many units in a bottle of wine?
About nine to ten at 12 to 13%: 750x13/1000 = 9.75.
Do units differ by country?
Yes. UK units are 8 g, US standard drinks 14 g, with other sizes elsewhere.
Can I save units for the weekend?
Bingeing raises acute risk even inside weekly totals. Spread them.
What about pregnancy?
Guidance is no alcohol. No safe amount is established.