Question 1

How is BAC calculated?

Accepted Answer

The standard Widmark formula: alcohol consumed in grams, divided by body weight times a distribution ratio, minus elimination over time (about 0.015% per hour). It's the same math used in textbooks, and like all formulas it's an estimate; food, medications, and individual metabolism shift real values meaningfully.

Question 2

What BAC is the legal driving limit?

Accepted Answer

0.08% in most US states, 0.05% in Australia and much of Europe, and zero for many new and commercial drivers. Impairment measurably begins around 0.02%, well below every legal limit, which is why the only safe number behind the wheel is zero.

Question 3

How long until my BAC is zero?

Accepted Answer

You eliminate roughly 0.015% per hour and nothing speeds it up: not coffee, cold showers, or food after the fact. From 0.08%, that's five to six hours; sleep doesn't pause the clock but it doesn't accelerate it either.

Question 4

Can I use this to decide if I can drive?

Accepted Answer

No, and we mean that. This is an educational estimate with real error bars. If you've been drinking at all, arrange another way home; the calculator exists to show how fast the numbers climb, not to hand out permission slips.

BAC Calculator

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