Total THC, mg/g vs mg per unit, the excise stamp and the packaging date: a plain-language guide to every legal cannabis label sold in Ontario.
To read a Canadian cannabis label, start with three things on the front: Total THC, Total CBD and the unit they are measured in (mg/g for flower and extracts, mg per unit or per package for edibles). Then check the red standardized cannabis symbol, the yellow health warning, the provincial excise stamp and the packaging date.
Every legal product on the shelf in Ontario follows the same federal rules, set out in the Cannabis Regulations and explained in Health Canada's guide on how to read a cannabis product label. Once you know the layout, you can compare any two products in seconds.
The front of the package
The main panel of every package carries:
- The brand name. A small logo may appear too.
- The standardized cannabis symbol. A red octagon with a cannabis leaf and the letters THC. Health Canada says it is required on the front of products with more than 10 micrograms of THC per gram.
- A health warning message in a yellow box. The regulations require these messages to rotate across a brand's packages, so two packs of the same product can carry different warnings.
- Total THC and Total CBD. The numbers most people shop by.
THC vs Total THC
"Total THC" is the quantity of THC the product could yield, taking into account the potential to convert THCA into THC. That is the wording the Cannabis Regulations use. Because the total figure accounts for THCA that can convert into THC, it gives you a realistic number to compare.
The same logic applies to Total CBD, which accounts for CBDA converting to CBD.
Some packages also print separate "THC" and "CBD" figures. When you are comparing products, use the totals: they are the figures the regulations require on every label.
The units change by product type
This is where most confusion comes from. A big number on a vape and a small number on a chocolate are not measured the same way.
| Product type | How Total THC appears |
|---|---|
| Dried flower | mg per gram (mg/g) |
| Pre-rolls | mg/g, plus the number of units and the weight of each |
| Vapes and concentrates for inhalation | mg/g |
| Edibles in pieces | mg per unit ("Total THC per unit") and mg per package |
| Edibles not in pieces, such as a drink | mg per package |
| Oils with a dispenser | mg per activation |
Converting mg/g to a percentage: divide by 10. Health Canada's own guidance writes it as "10% (100 mg/g)", so 200 mg/g is 20%.
Working out the total in a package: multiply the mg/g figure by the net weight. Health Canada's example: a 30 g package labelled "Total THC 180 mg/g" contains 5,400 mg of THC in total.
For edibles, read both lines. A package showing "Total THC per unit 2.5 mg" and "Total THC 10 mg" holds four pieces of 2.5 mg each. Federal rules cap edible cannabis at 10 mg of THC per package, which our edibles guide explains.
The excise stamp
Look for the excise stamp on the package. Health Canada says the excise stamp tells you the product came from a Health Canada licence holder, and each province and territory has a different coloured stamp. Some very low-THC products (under 10 micrograms per gram) and prescription products do not need one.
A missing stamp on a product sold as recreational cannabis is a red flag. Our post on how to tell if a dispensary is licensed covers the other signs of the legal market.
Everything else the label must show
Turn the package over and you will find the rest of the required information:
- Product class: dried cannabis, edible cannabis, cannabis extract, cannabis topical and so on.
- Net weight or volume, and for products in units, the number of units and the weight of each.
- Recommended storage conditions.
- "KEEP OUT OF REACH OF CHILDREN / TENIR HORS DE LA PORTÉE DES ENFANTS".
- Lot number and packaging date.
- The licensed processor's name, phone number and email, so you can report a quality problem.
- Intended use: inhalation, ingestion or skin application.
Extra information for edibles and extracts
- Ingredients, listed in descending order of weight, are required for extracts, edibles and topicals.
- Edibles must also list food allergens, gluten and added sulphites, and carry a nutrition facts table.
- Extracts must list any food allergens.
What the label does not have to say
Health Canada notes that a manufacturer may add an expiry date, a strain name or extra warnings, but none of these is required. That is why you can find two similar products where one names its strain and the other does not.
Words like indica, sativa and hybrid are not part of the required label at all. We explain what they do and do not tell you in Indica, sativa, hybrid: what the labels mean.
Use the packaging date
Because an expiry date is optional, the packaging date is your most reliable freshness signal, especially for dried flower and pre-rolls. Staff can show you the packaging date on any product before you buy.
A quick label checklist
- Find Total THC and Total CBD.
- Note the unit: mg/g, mg per unit or mg per package.
- Check the net weight and number of units.
- Confirm the excise stamp and the standardized symbol.
- Read the packaging date.
- For edibles and extracts, scan the ingredients and allergens.
Lower your risks
Health Canada's lower your risks guidance suggests choosing products with a low amount of THC and an equal or higher amount of CBD, looking for edibles with 2.5 mg of THC or less, and waiting to feel the effects before taking more. Never drive after using cannabis, and keep every product in its original child-resistant package, away from children and pets.
Visit Sugar Beach Cannabis
Want to practise reading labels with someone who reads them all day? Sugar Beach Cannabis is at 192 Queens Quay East, Unit A5, beside Sherbourne Common. Browse the live menu, which shows Total THC and CBD for every product, then order online and pick up in store. New to dispensaries? Start with our first-time guide, or contact us and learn more about the store.
Frequently asked questions
What does Total THC mean on a cannabis label?
Total THC is the amount of THC the product could yield, taking into account the potential to convert THCA into THC. It is the figure the Cannabis Regulations require on the label and the best number for comparing products.
How do I convert mg/g to a THC percentage?
Divide by 10. Health Canada writes it as 10% (100 mg/g), so a label showing Total THC 250 mg/g is 25% THC.
What is the excise stamp on cannabis packaging?
Health Canada says the excise stamp shows the product came from a Health Canada licence holder. Each province and territory uses a different coloured stamp, and some very low-THC and prescription products do not need one.
Do cannabis labels in Canada have an expiry date?
Not necessarily. An expiry date is optional, but every label must show the packaging date and lot number, so the packaging date is the most reliable freshness check.
Why does an edible label show two THC numbers?
Edibles sold in pieces show Total THC per unit and Total THC for the whole package. A package with 2.5 mg per unit and 10 mg in total contains four pieces.
This article is general information about cannabis rules and products in Ontario, not legal or medical advice. Rules change: check the official sources linked above. Cannabis is for adults 19+. Never drive impaired.
