How many grams in a CBD joint, and how long do 5 g last?

Nobody weighs their joints, and older estimates ran from 0.3 to 1 g. Greg Ridgeway (University of Pennsylvania) and Beau Kilmer (RAND Corporation) approached the question through prices. Their data were 10,628 cannabis purchases, joints and loose herb, reported between 2000 and 2010 by people arrested in the United States. By matching the price paid to the weight bought, they put the average weight of a joint at 0.32 g, within an interval of 0.30 to 0.35 g. The study was published in Drug and Alcohol Dependence.

Earlier figures were higher. The White House drug policy office used 0.5 g per joint, as the University of Pennsylvania's news release notes.

The benchmark has three limits. It describes cannabis bought in the United States; CBD flower sold in France was outside its scope. The weight was inferred from prices, and nobody put a joint on a scale. It also counts herb only: a joint of the same size rolled with tobacco holds less flower, and less still as the tobacco share rises. Our alternatives to tobacco in a joint cover that point. The sums below use 0.32 g; weigh one of your own joints if you want to redo them with your own figure.

The percentage on a product page is a share of the dry flower's weight, so a flower at 11% CBD contains 110 mg of CBD per gram. One multiplication gives the answer: joint weight × percentage.

When you do this calculation, keep the displayed reference values apart from the results of a batch certificate. On 24 September 2026, the Sour Spritz page shows 12.9% CBD in its reference profile, under a name that says 15%. The Strawnana page shows 12.3% under a name that says 11%. With these stated values, a 0.32 g joint holds 41.3 mg and 39.4 mg of CBD respectively. Without a dated certificate matching the batch, nobody can check these figures against what a given pouch contains. The same pages also list CBDA, the acid form of CBD, part of which heat turns into CBD.

Some of the CBD burns off in the tip, and some leaves in smoke that is never inhaled. The share that reaches the circulation is called bioavailability, and for smoked CBD it rests on one study. In 2018, a systematic review in Frontiers in Pharmacology collected the pharmacokinetic measurements of CBD in humans, keeping 24 publications out of 792 screened. Only one of them reports a bioavailability. In 1986, five men smoked a cigarette containing 19.2 mg of CBD in a laboratory. On average 31% reached their blood, with a standard deviation of 13 points between individuals.

THC has far more data. A 2007 review puts THC's bioavailability by smoking at 2 to 56%. The author links part of that range to smoking habits: how many puffs, how long and how far apart, how long the smoke is held, and how much is inhaled. There is no sign that CBD behaves differently. The "about 11 mg" in the table is an order of magnitude; nobody measured it.

Moving from an 8% flower to a 14% flower multiplies the CBD in the joint by 1.75. Smoking technique can shift the absorbed share much more than that, if the 2 to 56% measured for THC is any guide. The flower's percentage therefore cannot fix an amount to the milligram.

No authority sets an amount of smoked CBD either. Europe's only official benchmark is about 2 mg a day for a 70 kg adult, published by EFSA on 9 February 2026. It covers CBD taken by mouth as a food supplement at least 98% pure, and applies to neither smoke nor flower. Our article on EFSA's 2 mg benchmark sets out its limits. This guide describes amounts and does the arithmetic. It recommends no amount to consume.

THC counts as well. At 0.30% Δ⁹-THC, the maximum set by the French order of 30 December 2021, a 0.32 g joint holds up to 0.96 mg of it. On the road, article L235-1 of the French Highway Code punishes driving after drug use revealed by a test with three years in prison and a €9,000 fine, and sets no minimum threshold. Smoking is banned in places of collective use (article L3512-8 of the Public Health Code) and in a car carrying a minor (article L3512-9). Our article on smoking hemp and what the law says gives the full legal picture.

Divide the pouch weight by 0.32 for the number of joints, then by your pace for the duration. A gram gives a little over three joints.

The second column answers "how much for a month": between 1.4 and 19.2 g. For 0.5 g joints, multiply those grams by 1.56 and divide the durations by 1.56 as well.

Six 0.32 g joints come out of a 2 g pouch, which is enough to try a variety. Bigger pouches cost less per gram, though the flower ages while you work through it.

In 2020, an Israeli study in Frontiers in Plant Science followed flowers stored for a year. The terpenoids, which carry the smell, had lost more than 50% within four months, whatever the storage temperature. Cannabinoids fell by 26% on average over twelve months. At one joint a week, a 10 g pouch lasts 31 weeks, over seven months, so the last of it will have lost much of its aroma. Choose the pouch you will finish within four months at your own pace.

To slow the loss, keep the flowers whole, in a closed jar, out of the light and somewhere cool. Our guide to storing CBD flowers gives the humidity range to aim for: 55 to 65%.

A joint costs the price per gram × 0.32. The Strawnana, Sour Spritz and Confidential Weed pages share the same price grid; the last of these has a reference profile stating 7.1%.

Prices displayed on 24 September 2026. The variety drives the price more than the percentage does. Blood Orange, stated at 11.5%, is displayed at €6.45 per gram in the 2 g pouch, or €2.06 per joint, which is more than Strawnana at 12.3%. To compare flowers with different percentages, work out the price per 100 mg of CBD, as in our article on CBD prices in France in 2026. The price per gram of cannabidiol also works, as for CBD flowers in 100 g pouches. The CBD flowers category groups the varieties; a new batch may show a different percentage.