How long does Nicotine
stay in your system?
Tell us when you took it and how much — see exactly what's left right now.
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What is the half-life of Nicotine?
Nicotine (Nicotine) has an estimated half-life of about 2 hours. The amount in your body is reduced by about half on that schedule. Average half-life ~2 hours per UpToDate and published nicotine pharmacokinetic literature. Cigarette absorbed dose ~1.0-1.5mg per Medical News Today / NEJM (Henningfield 1995); pouch and gum at standard 4mg labeled strength.
Nicotine itself clears fast — its roughly 2-hour half-life is one of the shortest of any commonly used substance. But your liver converts nicotine into a byproduct called cotinine, which has a half-life of around 16 to 20 hours, nearly ten times longer. That difference is the whole reason nicotine drug tests don't actually test for nicotine: they test for cotinine, because nicotine itself is mostly gone within a day while cotinine sticks around long enough to be a reliable marker of use.
How does this calculator work?
This tool applies the formula Remaining = Initial × 0.5^(elapsed time ÷ half-life) to the half-life value above. Enter your amount and when it was taken, and it estimates how much is mathematically remaining right now, plotted on a chart and timeline that show real clock times rather than abstract durations, so you can see, for example, that "8:35 PM" is the dose and "9:35 PM" is one hour later, not just "1 hour."
How long does Nicotine stay in the body?
Based on a 2 hours half-life, it takes roughly five to seven half-lives for the mathematical model to reach a trace amount, generally under 2% of the original dose. Individual elimination varies with metabolism, dose, organ function, genetics, and other factors this calculation doesn't see.
This calculator's chart and timeline are showing you nicotine itself, not cotinine — so don't mistake the 'trace amount' point on this chart for when a nicotine/cotinine test would turn negative. Nicotine drops to a few percent of its starting dose within 10–14 hours given its 2-hour half-life, but cotinine, the actual thing most drug tests detect, can remain measurable in urine for several days to a few weeks in regular users, and in blood for up to 7–10 days.
Frequently asked questions
Is this medical advice?
No. This is a mathematical estimate only, not medical advice. It doesn't account for individual metabolism, organ function, drug interactions, or absorption rate, and shouldn't be used for medication, dosing, driving, or health decisions. See our terms of use for the full disclaimer.
Why is this only an estimate?
Real elimination depends on age, weight, liver and kidney function, genetics, and other medications, none of which this calculator can know. It applies one published half-life value to a simple decay curve rather than a personalized pharmacokinetic model.
If nicotine's half-life is only 2 hours, why does a nicotine test stay positive for days?
Because standard tests check for cotinine, nicotine's metabolite, not nicotine itself. Cotinine's half-life is roughly 16 to 20 hours, so it accumulates and lingers for days even after the nicotine that produced it is essentially gone.
Does smoking versus vaping versus pouches change the half-life?
The roughly 2-hour half-life for nicotine itself is similar across delivery methods once it's absorbed — what differs more is absorption speed and total dose per use (a cigarette delivers a smaller absorbed dose, around 1–1.5mg, than many vape sessions or strong pouches).
Can this tell me when Nicotine is completely gone?
Not precisely. Exponential decay approaches zero but never mathematically reaches it. After about five to seven half-lives, the remaining amount is a trace consistent with being effectively eliminated for most practical purposes.