Friday, July 19, 2024

Do You Know How Much THC Is In A Joint? Here’s How You Can Figure It Out

If you don’t mind a little arithmetic, calculating the accurate measure of THC in your joint can be easy to determine. Here’s how.

This article originally appeared on and has been reposted with permission.

One of the common questions novice and regular tokers have about their joints is: “What’s the estimated milligrams of THC in a joint?” The answer to this isn’t as straightforward as you’d like.

marijuana bud joint
Photo by athima tongloom/Getty Images

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In 2016, a Drug and Alcohol Dependence study suggested that a 0.3g cannabis blunt contains approximately 20mg of tetrahydrocannabinol. They also pointed out that this amount isn’t definite, as there are different strains of cannabis. In addition, the study noted that the total milligrams of THC in a joint could be determined by the part of the plant being smoked and the strain’s potency.

The amount of THC in a regular joint depends on so many variables. However, if you don’t mind a little arithmetic, calculating the accurate measure of THC in your joint would be a walk in the park once you’re done with this piece. You will also get to understand the various factors that determine how much THC is in your joint, as well as their impact on your health.

Calculating the Total Amount Of THC in a Joint

A standard analytical testing lab measures the theoretical maximum amount of THC that could be in a joint using the mathematical expression: “THC max = THC + THCA / 358.48 * 314.47.”

This expression gives the lab an estimated amount of THC in a blunt. If you often purchase blunts from legal dispensaries, you may notice this estimate written on the product’s package. This mathematical formula can estimate the strength of various cannabis strains.

It all gets a bit complicated here. There could be a notable difference in how much THC you have in your joint and how much THC you can consume in one session.

The fact that a joint contains up to 20mg of THC does not mean you would ingest the entire amount. This situation can be traced to the availability of THCA (THC in its non-psychotropic form) in an unignited joint.  THCA in a joint is converted to THC when ignited. This process is chemically known as decarboxylation. It describes the removal of carboxyl from THC acid.

The temperature, as well as the amount of time it takes for decarboxylation to occur in the joint, determines the total milligrams of THC you would consume in one joint. It’s been reported that at least 40% of THC is lost when smoking a joint.

Factors to Consider When Calculating THC

Four factors determine how many milligrams of THC you can consume in a joint: potency, joint size, bioavailability, and physiology.


The amount of smoke you inhale from a joint determines how much THC would be delivered. The more you inhale and the higher the strength of the weed, the more THC would be ingested. It’s important to stress that it is impossible to ingest all the THC present in the joint due to loss from combustion, inhalation, and uneven decarboxylation.

Joint Size

Joint sizes vary. Some weigh 0.3g, while some could weigh 0.66g and above. The amount of weed rolled up in your joint significantly affects how much THC is ingested. The smaller the joint, the lower the amount of THC delivered into your system. The longer or wider the joint, the more THC would be available for consumption.

Note that it is preferable to avoid longer and wider joints because they take more time to burn. The THC molecules are either burned off before you can consume them, or they’re taken away by air resistance. It’s best to have multiple smaller joints than a single big joint. More cannabis per joint; hence more THC enters your bloodstream.


Bioavailability is a term that describes the amount of a cannabinoid that makes its way into a body’s circulation after consumption.

Smoking joints is one of the easiest ways of increasing the bioavailability of cannabinoids, unlike eating edibles or other cannabis-infused products. When you smoke, the THC gets to your endocannabinoid system and brain in no time, as it is almost immediately absorbed into the bloodstream. When inhaled into the lungs, the smoke has a unique ability to cross the blood-brain barrier easily. There’s no waiting period for the cannabinoids to breakdown. They are absorbed quickly.

marijuana joint
Photo by RODNAE Productions from Pexels

RELATED: How To Prevent Uneven Burning In Your Rolled Joints

However, all these don’t mean no THC is lost after inhalation. Most studies show that THC bioavailability is capped at 30%. However, this may vary based on the toker.

The more bioavailable THC is in your bloodstream, the higher your buzz will be. For instance, since a 0.3g joint contains 20mg THC, 20% of this gives you a low buzz, 30 to 40% delivers a medium buzz, and 50% is highly potent.

The Smoker’s Physiology

Everyone has different body chemistry. There is no standard way for the human body to break down or tolerate THC. How your body takes in THC is determined by how much smoke you’ve inhaled, your lungs’ capacity, and how much THC is exhaled with the smoke.

A novice reacts differently to THC than a regular or consistent user. The more you consume joints, the higher your tolerance gets; hence, the more THC your body can handle. Also, users react differently to THC, regardless of the strain’s potency.

How Much THC Can I Take In

Here’s an easy experiment you could try to figure out how much THC you consume in a blunt.

Step 1: Check the label to find out how many milligrams of THC is in the joint you’re about to smoke.

Starting from the first puff, count the total drag you take till you’re either satisfied or done with the joint.

Step 3: Using the Max THC expression, figure out the total milligrams of THC in the joint.

Step 4: Divide the Max THC by the total number of puffs taken. This would give your an estimate of your THC consumed.

Note that there’ll always be an error factor in this experiment.

Final Note

If you don’t have the patience to do these arithmetics, a more leisurely, though expensive way to determine how much THC you’ve consumed accurately is through blood tests. It’s the only way to know for sure.

This article originally appeared on and has been reposted with permission.


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