Cocaine itself has a very short half-life (30–90 minutes), but its primary metabolite benzoylecgonine has a half-life of 5–8 hours and is detectable in urine for 2–4 days after occasional use and up to 14 days after heavy or prolonged use. When cocaine is consumed with alcohol, the liver produces cocaethylene, which extends detection windows and significantly increases health risks.
What this calculator does
Urine tests detect benzoylecgonine, not cocaine itself. The standard cutoff is 300 ng/mL for screening and 150 ng/mL for confirmation. Because benzoylecgonine has a much longer half-life than cocaine, urine detection extends well beyond the period of psychoactive effects.
How it works
Cocaethylene formation (when cocaine is used with alcohol) extends detection times by 20–30% and carries significantly higher cardiovascular toxicity. This metabolite is uniquely produced by the combination and is not formed from either substance alone.
Blood tests can detect cocaine for 12–48 hours and are primarily used in emergency medical settings and accident investigations. Saliva testing has a 1–2 day window and is used in some workplace and roadside screening programs.
When to use this calculator
Use this calculator as a starting point for any health or fitness goal that requires a numeric benchmark. The result is an estimate, not a diagnosis — but it provides a concrete figure to track against over time.
Common mistakes
The most common mistake is treating the result as a precise measurement rather than an evidence-based estimate. All body metric calculators have margins of error — use the result as a tracking baseline, not a clinical diagnosis.
Real-world scenarios
A personal trainer uses the calculator with a new client to set a measurable starting point. Re-running the calculation at 4-week intervals provides an objective progress metric that supports motivation and programme adjustments.
Formula
Benzoylecgonine Clearance
Clearance Time ≈ 5 × Half-life (5-8h) = 25-40 hours for single use
Five half-lives are needed to eliminate >96% of a substance. Benzoylecgonine's 5–8 hour half-life means most clearance occurs within 25–40 hours for occasional use, but chronic use causes accumulation.
Worked example
Occasional user, single use, 75kg body weight.
Cocaine half-life: 30–90 minutes (acute effects)
Benzoylecgonine half-life: 5–8 hours
5 half-lives for clearance: 25–40 hours
Urine detection window: 2–4 days
Blood: 12–48 hours
Hair: up to 90 days
Result: For occasional use, urine tests are the primary concern with a 2–4 day detection window. Blood clears within 48 hours. If used with alcohol, add 20–30% to all detection estimates.
Frequently asked questions
How long does cocaine stay in urine?
Occasional use: 2–4 days. Regular use: 5–7 days. Heavy chronic use: 7–14 days. The metabolite benzoylecgonine is what tests detect.
Does alcohol extend cocaine detection time?
Yes. Concurrent use produces cocaethylene, which has a longer half-life than benzoylecgonine and extends detection by approximately 20–30%.
How long do cocaine effects last?
Snorted: 15–30 minutes. Smoked (crack): 5–10 minutes. This short duration often leads to repeated use, which significantly extends detection times.