Units to Drive Calculator
Rough estimate only — metabolism varies wildly. The only guaranteed-legal amount is zero.
Result
Units to Drive Calculator — FAQs
What is the UK drink-drive limit?
80mg of alcohol per 100ml of blood (0.08% BAC) in England, Wales and Northern Ireland; 50mg (0.05%) in Scotland — roughly aligned with most of Europe.
How many units can I drink and drive?
There's no safe number — the same drinks produce wildly different BAC by weight, sex, food and metabolism. The estimate above is a rough guide, not a legal defence.
How fast does alcohol leave your system?
About 1 unit (0.015% BAC) per hour — nothing speeds it up. A heavy night can leave you over the limit well into the next morning ('morning after' driving is a major source of convictions).
Is this calculator accurate enough to rely on?
No — it's a Widmark estimate with average body-water ratios. Real BAC varies ±20%+ per person. If you're asking the question, the safe answer is don't drive.
Need a Custom Tool Built?
We build calculators, estimators and internal tools for businesses in the UK and North America.
Get a QuoteEmbed this Units to Drive Calculator on your site
Free to use — paste this snippet into any webpage. It auto-resizes and includes a small attribution link. Add ?theme=dark to the iframe URL for dark mode.
Need help? See the embed guide for WordPress, Webflow, Squarespace & more.