Ontario's 30-Gram Rule: How Cannabis Possession Limits Compare Across Flower, Edibles, Extracts and Oils

“Thirty grams” is the number everyone repeats, and it is correct — but it only tells the whole story if what you are carrying is dried flower. Put a bag of gummies, a vape cartridge and an eighth in the same tote and the arithmetic stops being obvious. Canada's Cannabis Act settles it with an equivalency table, and it is worth understanding before you assume a small package is automatically within the limit.

The baseline: 30 grams, in public, at 19 or older

Federal law sets a maximum public possession limit of 30 grams of dried legal cannabis, or its equivalent, at any one time. In Ontario the minimum age is 19, and that same 30-gram figure is what an authorized cannabis store or OCS.ca will allow in a single transaction. It is a limit on what you carry in public. It is not a monthly purchase quota, and it is not a rule about how much you may keep at home.

The equivalency table, in plain terms

Health Canada converts every other product format back to dried flower. One gram of dried cannabis is treated as equal to:

• 5 grams of fresh cannabis
• 15 grams of edible product
• 70 grams of liquid product
• 0.25 grams of concentrate
• one cannabis plant seed

Scale those conversions up to the full limit and the picture changes considerably. Thirty grams of dried flower buys you the same allowance as 150 grams of fresh cannabis, 450 grams of edibles, 2,100 grams of liquid product, 7.5 grams of concentrate, or 30 seeds.

Where the comparison gets counterintuitive

Two things tend to surprise people.

First, edibles are generous by weight. Four hundred and fifty grams is close to half a kilogram of product, and a standard package of gummies or chocolates weighs a small fraction of that. In practice, an edibles-only shopper will run into their wallet long before they run into the possession limit.

Second, concentrates are strict. The full allowance is 7.5 grams — shatter, rosin, live resin, hash and similar products all count against it. Because concentrates are commonly sold in one-gram and half-gram formats, a modest collection can approach the ceiling faster than most people expect.

It is also important to note that the equivalency is a weight conversion, not a potency conversion. THC content does not enter the possession math at all. A low-dose gummy and a high-dose gummy of identical weight count identically against your limit.

What the store handles for you

At authorized cannabis stores and on OCS.ca, everything in your basket is automatically converted into its dried-cannabis equivalent, and you may purchase up to the 30-gram equivalent in one transaction. That means a single legal purchase, by definition, cannot put you over the line. The exposure comes from stacking — an order that arrived this week added to whatever was already in your bag from last week.

For anyone who wants to check a mixed basket precisely, Health Canada publishes an online possession limit calculator that applies the same conversions. It is the most reliable way to settle the question for an unusual combination of formats.

At home versus in public

There is no formal limit on how much legally purchased cannabis you may store at home, provided it came from a legal source and is stored securely and out of reach of children and pets. The 30-gram figure governs public possession specifically. Someone with a well-stocked cupboard is not in breach of the possession limit simply for owning it — the question is what leaves the house with them.

How to work it out for yourself

If you carry only flower, the rule is simply the printed weight on the packages you have with you. Add them up and stay under 30 grams.

If you carry a mix, convert everything to dried-gram equivalents first, then total it. Divide edible weight by 15, liquid weight by 70, fresh weight by 5, and multiply concentrate weight by four. Concentrates are almost always the binding constraint, so start there.

And if you are travelling with more than a single day's worth — heading to a cottage, say, or moving between homes — the simplest approach is the safest one: work out the equivalent, keep the public-facing total comfortably under the ceiling, and leave the remainder stored at home rather than carrying the whole supply at once.