Cannabis Weights and Measurements, Explained

Cannabis is sold in a vocabulary borrowed from imperial measurement and then abbreviated by decades of informal use.

An eighth of what, exactly? Most people never ask.

Here is the full translation, plus the part that actually matters, which is how to decide what size to buy.

The Basic Units

Everything is a fraction of an ounce, which is 28 grams. Dispensaries round it — the legal ounce in most markets is 28.35 grams, but 28 is the working number.

Common name	Fraction of an ounce	Grams	Typical joints
Gram	1/28	1g	2–3
Eighth	1/8 oz	3.5g	7–10
Quarter	1/4 oz	7g	14–20
Half	1/2 oz	14g	28–40
Ounce	1 oz	28g	56–80

Joint counts assume roughly a third to a half gram each, which is where most people land. You will also hear “dub” or “eighth” used loosely, and older informal terms that predate legal retail. In a licensed dispensary the menu will just say the weight.

Why the Eighth Is the Default

The eighth is the standard unit almost everywhere, and it is not an accident.

Three and a half grams is roughly a week to two weeks of moderate use for most people. It is enough to get a real sense of a strain without committing to a large quantity, and it is small enough to stay fresh through the time it takes to finish it.

That last point matters more than the price break on larger quantities. Flower degrades, and how you store it only slows the process.

An ounce at a better price per gram is only better value if you finish it while it is still good. Half of it going stale in month three erases the discount entirely.

The Price Per Gram Curve

Larger quantities cost less per gram. That is consistent across essentially every dispensary.

The savings are real but they flatten out. Going from a gram to an eighth is usually a substantial per-gram improvement. Going from a half ounce to a full ounce is often a much smaller step.

Where the curve sits depends on the market and the product tier. Our breakdown of what weed costs in New Jersey gets into the actual numbers and where taxes land in the total.

Concentrates and Edibles Use Different Units

Flower weights do not carry over.

Concentrates are sold by the gram, typically in half-gram and full-gram increments. A gram of concentrate is a lot — considerably more sessions than a gram of flower, given the potency difference. If you are new to the category, a beginner’s guide to dabbing covers why dose size shrinks so dramatically.

Edibles are sold by total milligrams of THC per package and per piece. A 100mg package with ten 10mg pieces is the common format. Homemade edibles are a different matter, since potency there is estimated rather than measured — our cannabutter guide works through that arithmetic.

Vape cartridges are sold by volume, usually 0.5g or 1g.

Tinctures are labeled by total milligrams in the bottle, which you then divide by dropper volume — the arithmetic is covered in how to use cannabis tinctures.

Purchase Limits

Both New Jersey and California cap how much you can buy in a single transaction, and the categories are counted separately.

The limits are generous enough that most customers never approach them, but they exist and staff will enforce them. They also differ between the two states, along with a few other rules worth knowing if you shop in both — we cover that in buying cannabis in New Jersey vs California.

Because these limits are set by regulators and get adjusted periodically, the current numbers are worth confirming at the counter rather than assuming.

How to Decide What to Buy

A reasonable way to think about it:

• Trying something new? Buy a gram or an eighth. There is no reason to commit further.
• Something you already know you like? A quarter is usually the sweet spot between price and freshness.
• Regular, consistent use? A half or an ounce makes sense if you will finish it in six to eight weeks.
• Buying several different strains? Multiple eighths beats one large quantity of one thing.

The most common mistake is buying too much of something unfamiliar because the per-gram price looked good. The second most common is buying too little of something excellent and having it gone in four days.

A Note on Accuracy

Licensed dispensaries weigh product and are subject to accuracy requirements. Minor variation exists — a 3.5g eighth may weigh 3.5 or 3.6 — but systematic short-weighting is a compliance issue, not a normal cost of doing business.

If you weigh something at home and it is meaningfully light, that is worth raising with the shop. It is the sort of thing a licensed retailer wants to know about, and it is another practical difference between buying licensed and buying elsewhere.

Putting It Together

Twenty-eight grams to an ounce, and everything else is a fraction of that.

Start at an eighth for anything new, size up for things you have already confirmed you like, and be honest with yourself about how fast you actually go through it. That is most of what the vocabulary is for.