((num x 10) - (hrs x 7.5)) ÷ (kg x gender)

bac ÷ 0.015

**num**: number of standard drinks

**hrs**: drinking time in hours

**kg**: your weight in kilograms

**gender**: 5.5 for women and 6.8 for men

**0.015**: alcohol dissipates at 0.015g per hour

**abv**: alcohol by volume

**0.8**: specific density of alcohol

**7**: the number of calories in a gram of alcohol

(litres) x (alcohol by volume) x (alcohol density)

750ml at 13% has 7.7 standard drinks

0.75 x 13% x 0.789 = 7.69

abv std drink |
12.5% 7.4 |
13.0% 7.7 |
13.5% 8.0 |
14.0% 8.3 |

calories | 518 | 546 | 567 | 588 |

grams alcohol | 525 | 546 | 567 | 588 |

Multiply the number of standard drinks by 70. Why 70? Because 1g alcohol has 7 calories and 1 standard drink has 10g alcohol.

num std: | = | calories: |

The formula is: ((abv x 0.8 x ml) ÷ 100) x 7

abv: | ml: | = |