How Long Does a Joint Stay in Your System?

Daniel Miller
Daniel Miller, Ph.D, Drug Testing Specialist

Last updated on Apr 9, 2024

Even after the effects of weed are long gone, a single joint will stay in your system – i.e., it will still be detectable by a drug test – for at least 7-8 days. After that, you will be able to pass a urine drug test because the amount of weed in urine would’ve become below the cutoff level of 20ng/ml.

Now, there are a lot of factors that can affect how long does a joint stays in your system; surprisingly, and unfortunately, it can be much longer for some people.

But wait, there’s good news! You can use a calculator to get a more precise time for your particular situation.

Today, I’m going to explain to you the justification behind why a single joint takes different time to clear different body types and help you understand how to use the calculator to estimate your particular clearance time.

General Assumptions

As I’ve already mentioned, there’s no way to determine exactly how much time is required for one joint to leave your system.

That’s because of different factors: the amount of weed in a joint, THC content, body mass, metabolism, etc. (We’ll get into these later.)

To be completely sure that our calculations will be as accurate as possible, we’ll have to make some general assumptions.

Let me guide you through these.

Amount of Cannabis that Constitutes a Joint

There are many answers to this particular question.

According to the Washington Post, the average joint contains 0.32g of weed. A different study shows that the average amount is 0.66g.

The federal government says that it’s 0.43g [4]. And a poll conducted at High Times says that the average joint contains 1g of weed.

To make calculations easier to proceed with, we’ll take 1g as our starting point, and we can scale it if needed.

weight of weed joint

Amount of THC in a Typical Gram

One gram of cannabis, i.e., 1000mg, contains 100-300mg of THC on average.

Different weed strains have been found to contain different amounts as well! For instance, raw cannabis flower is typically considered to contain 10 to 30 percent of THC.

We’ll split the difference and call it 200mg of THC for this article.

Strain THC content(%)
Memory Loss
GMO Cookies
Silver Haze

The Smoker

As I mentioned before, many factors influence how your body will process THC. These include the frequency of using weed, body fat, rate of metabolism, hydration, etc.

For this generalization, we’ll assume that the person is a first-time smoker with a fast metabolism and low body fat.

What Happens after We Smoke Weed

As you must know by now, the main active component of marijuana is delta-9-THC-COOH (THC). Let’s briefly run through what happens when we consume marijuana or any product containing THC.

When you smoke weed, it travels through the lungs, enters the bloodstream, makes its way to the brain, and gives you the high. Once in the liver, a glucuronide molecule is added to it, making it THC-COOH-glucuronide. This compound is then excreted along with bile into the intestines.

A part of the THC-COOH-glucuronide is excreted via stool and urine, and the remainder is reabsorbed into the bloodstream.

After all fun and games are over, some THC remains ‘trapped’ in body fat tissues since it is extremely fat-soluble. Simultaneously, the remainder is metabolized by the liver and excreted gradually through urine and stool.

When Will Marijuana Show Up on a Drug Test

If you’re a regular weed user, you’ll know that there are different types of tests used to detect its presence – blood, saliva, urine, and even hair!

Interestingly, these tests are not looking for THC but instead detect its metabolites.

Here’s a little info about each of the tests:

Type of Test Details
Urine The main metabolite detected: delta9-THC-COOH.

Cutoff value: typical 50 ng/mL in the US; the more sensitive cutoff of 20 ng/mL (less common)

Time-span: 3–4 days since the last use; for the most sensitive test, maximum times are 7-21 days

Hair The main metabolite detected: delta9-THC-COOH stored inside the hair shaft.

Cutoff value: as low as 1 pg/mg

Time-span: approximately 90 days after intake

Saliva The main metabolite detected: delta9-THC-COOH Cutoff value: as low as 0.5 ng/mL.

Time-span: 72 hours after intake

Blood The main metabolite detected: metabolites and delta9-THC-COOH.

Time-span: 12–24 hours; up to 7 days for very heavy users

For this article, we’ll use a cut-off value of 50ng/ml.

How Long Does THC Stay in Your System

To understand this concept, you need to learn a new term: half-life.

Half-life is the time it takes for half of the THC in the body to be excreted.

A study found that the excretion half-life during the first five days after weed intake was around 1.3 days (27 hours) for infrequent users. For frequent cannabis users, a half-life of 2 days (48 hours) was found, while some even reported half-lives of up to 10.3 days.

Obviously, half-lives would be longer for heavy users since the more cannabis consumed, the more time the body will need to remove it from your system actively.

So, How Long Does a Joint Stay in Your System?

We’ve covered everything we needed to know and understand before using the calculator and making our assumptions. So let’s dive straight into it!

How Long Does a Joint Stay in Your System for a drug test

A quick review before we start our THC math class: we’re assuming that a first-time, slim smoker with a fast metabolism smoked 1g of marijuana with 20% THC content, resulting in 200mg of THC in his body.

As per a study, when there was 27mg of THC in a joint, the amount of THC-COOH in the smoker’s urine was peaking at 180 ng/mL after 4 hours.

Using simple cross-multiplication: after smoking 200mg, the concentration of THC-COOH in the urine will be 1330ng/ml.

After 26 hours, the concentration will be 665ng/ml.

After 52 hours, it will be 332ng/ml.

And so on.

And fast forward to 130 hours – the concentration will become 40ng/ml, which is below the detectable level of urine drug test.

How long will this take, you ask? It’s for about 5 days and 10 hours. For a urine immunoassay drug test, the type that’s most commonly used, this is great.

But if you need to pass a gas chromatography urine drug test, which is a little more sensitive, the cutoff value is 20ng/ml, meaning you’ll need 2 more days for THC to become undetectable from your urine.

Bottom line: about 8 days will be enough to substantially lower the concentration of THC-COOH in the urine to below the detectable level of urine drug tests.

The THC-COOH concentrations on the chart above are slightly different than I write here. This is because the chart was made with our THC calculator, and it uses more data to calculate values, and it is much more precise.

Disclaimer: since there are many other factors involved, these calculations should be considered an approximation and used only as a general benchmark.

Factors That Impact the Time Marijuana Stays in Your System

The math is over. Congratulations, you made it this far!

Now let’s discuss all the factors that can influence the calculations we’ve so confidently made about THC clearance time.

Just a thought: regular cannabis consumers should, in general, anticipate that THC remains in their system for a longer period when compared with a first-time user. That’s because THC is a fat-soluble chemical.


Women usually metabolize THC at slightly slower rates, mostly because they have higher body fat levels compared to males, so they tend to store more THC.

Frequency of Use

This is the single most significant factor. First-time consumers can expect THC to remain in their systems for about 3 days. For those who take weed about 3 to 4 times a week, the detection window is closer to a week after the last usage.

However, for daily users, cannabinoids can be detectable in their systems for as long as 30 days and even more.

The potency of Marijuana Strain and Your Tolerance

As I mentioned, different strains of marijuana have different amounts of THC. For instance, kief, also known as cannabis crystals, takes longer to metabolize than cannabis with lower levels.

In short, the stronger the weed, the more time it will take to be broken down by your system.

Method of Consumption

The form in which you consume cannabis greatly affects how long it stays in your body. Smoking will make you high within minutes, while edibles take far longer to be metabolized.

Simply put, cannabis is excreted from the body faster when smoked or vaped, but if taken orally, you can expect it to linger in your system for longer.

Lung Capacity

When you smoke or vape weed, some factors such as how much you inhale and how long you hold your breath after each puff determine how much THC will enter and remain in your system.

Body Fat or Body Mass Index (BMI)

Being a fat-soluble chemical, THC binds to and is stored in fat in the body. Unfortunately, this makes it even tougher to get rid of.

This means that your weight or BMI (and metabolism, mentioned later) plays a major part in determining the time it takes for weed to leave your system – a higher percentage of body fat means a longer time to metabolize cannabis.


The faster your metabolism, combined with a lower percentage of body fat, the faster marijuana will be metabolized and excreted from your body.

However, metabolism can be influenced by age, exercise, and certain health conditions.

Drugs that Interact with CYP2C9 and CYP3A4 enzymes

CYP2C9 and CYP3A4 are two enzymes involved in the metabolic pathway of THC. Certain drugs can lower the levels of these enzymes, in turn increasing the levels of delta-9-THC in your system and decreasing its rate of removal.


Some people claim that conditions that might enhance the breakdown of lipids (fats), such as food deprivation, stress, exercise, or weight loss, can lead to bursts of the released or stored cannabinoids from adipose (fat) tissues.


Dehydration increases the concentrations of THC in your body. While flushing water into your system won’t make you pass a drug test, it will dilute its urine levels and make its removal from the body faster.

How Long Does One Puff Stay In Urine

Here is some important information for those who can’t resist puffing on weed.

On average, there are 25 to 30 puffs in a joint.

Yes, I know I said the math was over, but bear with me one last time!

Considering all the assumptions we’ve made earlier, the amount of THC in each puff will be 8mg, which will result in a 53ng/ml concentration of THC-COOH in the urine after you smoke.

Applying the same basic mathematics, the concentration will be below the detectable cutoff value of 20ng/ml in 2 days after smoking a single puff.

Is There Anything You Can Do To Metabolize THC Faster

If you’re running low on time and need an urgent detox, there are a few things you can do to speed up the excretion of weed from your system.

So there you have it, a comprehensive step-by-step review of how to calculate the time it will take to remove a weed joint from your system and what factors influence it.

Fee free to use these guidelines to make sure you’re ready for your next drug test. Good luck!

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The information on this website about detox products and synthetic urines is for educational purposes only. We do not endorse or condone their illegal use. Always consider the laws in your area and the potential legal consequences. Consult with a healthcare professional before using any products. Your responsibility and well-being are paramount.