CaffeineIQ

Make it more accurate

Thirty seconds. Every answer is optional and changes the numbers right away.

Do you smoke or vape nicotine daily?

Nicotine makes your body clear caffeine faster.

Are you on hormonal birth control?

Pills with estrogen can roughly double how long caffeine lasts.

Are you pregnant?

Caffeine clears more slowly during pregnancy.

How does coffee affect you?

Your own experience is a useful hint.

How much caffeine at bedtime bothers you?

This sets your sleep-friendly level. It's a rule of thumb, not a medical threshold.

Units

Liver conditions and some medications change how fast caffeine clears. If that applies to you, these numbers will be off; ask a clinician.

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