THC Detection Calculator
By Verdant Herbals · Updated 2026 · Estimates only — individual results vary
Use this free calculator to estimate how long THC metabolites are likely detectable in your system for a urine, saliva, blood, or hair drug test. Enter your usage pattern, body weight, and metabolism to get a personalized estimate.
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How Long Does THC Stay in Your System?
When you use cannabis, THC is broken down by your liver into metabolites — primarily THC-COOH. These metabolites bind to fat tissue and are released gradually over time through urine, stool, and sweat. Drug tests don't detect THC itself; they detect these stored metabolites.
How long they remain detectable depends heavily on how often you use, how much body fat you carry, how fast your metabolism runs, and which type of test is being administered.
Detection Windows by Test Type
*Hair tests reflect up to ~90 days of use because labs examine the first 1.5 inches of scalp hair, which grows at approx. half an inch per month. Single use may or may not appear depending on amount consumed.
What Factors Affect How Long THC Is Detectable?
- Frequency and quantity of use — the more and more often you use, the more metabolites accumulate in fat tissue
- Body fat percentage — THC metabolites are lipophilic (fat-soluble); higher body fat means more storage and slower release
- Metabolism rate — a faster metabolism processes and eliminates metabolites more quickly
- Hydration — staying well-hydrated helps flush metabolites through urine, though extreme over-drinking can cause a dilution flag on lab tests
- Exercise — physical activity burns fat and can speed metabolite release, but intense exercise close to a test may temporarily raise blood THC levels
- Test cutoff level — standard urine tests use a 50 ng/mL cutoff; some use 20 ng/mL which is more sensitive and catches users for longer windows. Learn about the 50 ng/mL threshold.
How to Get THC Out of Your System Faster
There is no method that can instantly eliminate THC metabolites — your body needs time. However, several strategies can accelerate the natural clearance process:
- Abstain completely — every day without use allows existing metabolites to clear
- Stay hydrated — drink 8–10 glasses of water daily to support kidney filtration
- Eat a clean, low-fat diet — reduces metabolite reabsorption from stored fat
- Exercise regularly — burns fat where metabolites are stored (stop 24–48 hrs before your test)
- Sleep well — the liver does peak detox work during sleep
- Use a THC detox kit — a structured supplement program like Verdant's 2-Day Kit combines herbal liver support, diuretics, creatine, and electrolytes to amplify your body's clearance rate over 48 hours
Frequently Asked Questions
For a single use: 3–7 days. Moderate use (a few times per week): 7–21 days. Daily use: 30–60 days. Chronic heavy use: up to 90 days. Urine testing is the most common type of drug screen because of its long detection window and low cost.
Saliva tests are most sensitive to very recent use. For occasional users, THC is typically detectable for 1–3 days. For heavy daily users, the window can extend up to 29 days. Saliva tests are commonly used for roadside and workplace testing due to easy collection.
Blood tests detect very recent use. For occasional users, THC is detectable for a few hours to 24 hours. In heavy users, it can remain detectable for up to 7 days. Blood testing is the most expensive and invasive option, so it's less common outside of medical or legal settings.
Hair follicle tests have the longest detection window — up to 90 days — because hair grows approximately half an inch per month and labs examine the first 1.5 inches from the scalp. Hair testing is better at identifying patterns of use over time than detecting a single recent episode.
Increased hydration speeds up urine output and helps flush metabolites, but it is not a guaranteed pass. Drinking extreme amounts of water can dilute your sample below normal creatinine levels, which causes the lab to flag the result as "dilute" — which may require a retest. A detox kit that includes creatine supplementation helps maintain normal urine markers while increasing fluid output.
The calculator provides estimates based on published detection-time research and population averages. It is not a guaranteed prediction — individual biology varies significantly. Use it as a planning guide, not a guarantee. For a more detailed breakdown, read our complete THC detection times guide.