On Canadian cannabis labels, converting potency is a single step: divide the mg/g figure by 10 to get the percentage. A product showing 194 mg/g Total THC is 19.4% THC. To find the milligrams in a specific serving, multiply that mg/g figure by the unit mass in grams. A 0.5 g serving of that same product delivers 97 mg of Total THC. These two rules let you convert cannabis measurements in Canada for almost every label you’ll encounter.
Quick anchors to keep in your back pocket:
- mg/g ÷ 10 = % (e.g., 80 mg/g = 8%, per Ottawa Public Health)
- mg per serving = mg/g × serving mass (g) (e.g., 194 mg/g × 0.2 g = 38.8 mg)
- 1 g = 1,000 mg — useful when cross-checking label math
- Common weights: 1 g, 3.5 g (eighth), 7 g (quarter), 14 g (half), 28 g (ounce), 448 g (pound by industry convention)
- Public possession limit: 30 g dried-cannabis equivalent for adults, under the Cannabis Act
- Schedule 3 equivalencies: 1 g dried = 15 g edibles = 70 g liquids = 0.25 g concentrates
Key takeaways
Accurate cannabis measurement conversion in Canada comes down to two rules: divide mg/g by 10 for percentage, and use Schedule 3 equivalencies to stay within the 30 g public possession limit.
| Point | Details |
|---|---|
| mg/g to percent | Divide the label’s mg/g value by 10 to get the percentage (e.g., 194 mg/g = 19.4%). |
| mg per serving | Multiply mg/g by serving mass in grams (e.g., 194 mg/g × 0.2 g = 38.8 mg). |
| Public possession limit | Adults may carry up to 30 g dried-cannabis equivalent in public under the Cannabis Act. |
| Schedule 3 equivalencies | 1 g dried = 15 g edibles = 70 g liquids = 0.25 g concentrates for possession math. |
| Use Total THC for inhalables | Total THC reflects post-heat potency and is the relevant figure for dried flower and vapes. |
Table of Contents
- Your printable cheat sheet for potency and weight
- How do you convert mg/g on Canadian labels to percent and mg per serving?
- What should you look for on a Canadian cannabis label?
- What do cannabis weight slang terms mean in Canada?
- What are Canada’s public possession limits and dried-cannabis equivalencies?
- Worked examples: label to percent, mg per serving, and possession math
- Why labelling precision and dosing caution matter
- The Montrose perspective on why accurate conversions protect you
- Sources
- FAQ
Your printable cheat sheet for potency and weight
Potency quick-reference
“Total THC” includes THCA converted on heating. “THC” alone is the measured pre-heat value and is typically lower.
Weight and slang quick-reference
Possession equivalency snapshot (Cannabis Act, Schedule 3)
The Cannabis Act — section 8 prohibits carrying more than the 30 g dried equivalent in public. Mix product classes and the equivalencies above determine your total.
Pro Tip: Health Canada expects cannabinoid values to be displayed with standardised numeric precision — typically three significant figures above 100 (e.g., 194 mg/g) and two figures below 100 (e.g., 75 mg/g). That rounding can shift your calculated mg by a small margin, so treat label numbers as close estimates rather than exact values.
How do you convert mg/g on Canadian labels to percent and mg per serving?
The math is straightforward once you know what each label field means.
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Identify the label format. Check whether the label shows mg/g, mg per unit, or a percentage. Dried flower and extracts typically use mg/g; edibles and capsules often show mg per unit. The Health Canada packaging and labelling guide sets out exactly which format each product class must use.
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Convert mg/g to percent. Divide by 10. The reason: mg/g means milligrams per 1,000 mg of product, so 100 mg/g = 10 g per 100 g = 10%. A product at 220 mg/g is 22% THC.
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Calculate mg per serving. Multiply the mg/g value by the serving mass in grams.
- 1 g serving at 220 mg/g: 220 mg
- 2.5 g serving at 220 mg/g: 550 mg
- 0.2 g puff at 194 mg/g: 38.8 mg
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Account for rounding. Health Canada guidance calls for three significant figures above 100 mg/g and two below. A label reading 75 mg/g could represent anywhere from 74.5 to 75.4 mg/g. For edibles and concentrates especially, that small window matters for dosing.
Key figure: Ottawa Public Health uses 80 mg/g = 8% CBD as a plain-language example of the divide-by-10 rule — a reliable mental shortcut for any Canadian label.
What should you look for on a Canadian cannabis label?
Reading a label confidently means knowing which fields to check before you do any math. The Government of Canada label guide explains each field in plain language.
THC vs. Total THC
“THC” on a label is the measured cannabinoid content before the product is heated. “Total THC” adds the potential contribution from THCA, which converts to THC when you apply heat. For inhalable products like dried flower and vapes, Total THC is the figure that best reflects the intoxicating effect you’ll actually experience. For edibles and capsules, the mg per unit figure is already the active amount.
mg/g vs. mg per unit
- Dried flower, pre-rolls, and extracts: expect mg/g
- Edibles, capsules, and beverages: expect mg per unit or mg per mL
Mixing these up is the most common conversion mistake. A 10 mg edible is 10 mg total, full stop. A 10 mg/g dried flower at 1 g is also 10 mg, but at 3.5 g it’s 35 mg.
What else to confirm before converting:
- Product class (dried, extract, edible, beverage) — determines which equivalency applies
- Net weight or volume — the denominator in your mg-per-serving math
- “Contains the equivalent of ## g of dried cannabis” statement, which appears on some products and does the possession math for you
- The standardised cannabis symbol (the red stop-sign-style icon), which confirms the product is regulated
For a deeper walkthrough of every label field, the Montrose cannabis product label guide covers each element with Canadian examples.
Pro Tip: If the label lists both THC and Total THC, always use Total THC for your potency calculations on inhalable products. The gap between the two figures can be significant on high-THCA flower.
What do cannabis weight slang terms mean in Canada?
Canadian buyers use a mix of imperial slang and metric grams, and the two systems don’t always line up cleanly.
- Gram (1 g): The smallest standard purchase unit at most retailers.
- Eighth (3.5 g): One-eighth of an ounce. The most popular purchase size in Canada, per Leafly’s visual weight guide.
- Quarter (7 g): Two eighths, or one-quarter ounce.
- Half (14 g): Half an ounce.
- Ounce (28 g): The industry standard rounding. A true imperial ounce is 28.35 g, but the cannabis trade rounds to 28 g universally.
- Pound (448 g): Calculated as 16 × 28 g, not the metric 454 g. If you’re buying bulk or large-format cannabis, that 6 g difference per pound adds up across multiple units.
Worth knowing: For typical inhalation, a single dose ranges from roughly 0.1 g to 0.5 g depending on tolerance and consumption method. A standard 3.5 g eighth contains anywhere from 7 to 35 individual puffs at those dose sizes — a useful frame when comparing price per gram.
For precise small-dose measuring, Measurement Canada sets requirements for scales used in cannabis retail to protect buyers from inaccurate weights at point of sale.
What are Canada’s public possession limits and dried-cannabis equivalencies?
Under Cannabis Act section 8, adults 18 and older may carry up to 30 g of dried cannabis equivalent in public. The Schedule 3 equivalencies convert other product classes into that single dried-equivalent number.
Schedule 3 equivalencies:
- 1 g dried cannabis = 15 g edibles
- 1 g dried cannabis = 70 g liquid cannabis (beverages)
- 1 g dried cannabis = 0.25 g concentrate
How to calculate a mixed basket:
- Divide each product’s weight by its equivalency factor to get dried-cannabis equivalent grams.
- Add all dried-equivalent values together.
- Keep the total at or below 30 g.
Example: You’re carrying 7 g dried flower + 30 g edibles + 0.5 g concentrate.
- Dried: 7 g ÷ 1 = 7 g equivalent
- Edibles: 30 g ÷ 15 = 2 g equivalent
- Concentrate: 0.5 g ÷ 0.25 = 2 g equivalent
- Total: 11 g equivalent — well within the 30 g limit.
Health Canada’s online possession calculator does this arithmetic for you if you would rather not do it by hand. Provincial and territorial rules can add further restrictions beyond the federal limit, so it’s worth checking your province’s specific rules. Ontario’s rules are covered in the Montrose public use guide.
Worked examples: label to percent, mg per serving, and possession math
Example A: dried flower at 194 mg/g Total THC
- Convert to percent: 194 ÷ 10 = 19.4% Total THC
- mg in a 0.2 g puff: 194 × 0.2 = 38.8 mg
- Possession equivalent: 1 g dried = 1 g equivalent. A 3.5 g eighth = 3.5 g dried equivalent.
Example B: edible at 10 mg per unit
- Dried-equivalent per unit: 1 unit ÷ 15 (equivalency factor) = 0.067 g equivalent
- Units to reach 30 g limit: 30 ÷ 0.067 = 450 units — edibles rarely constrain possession on their own.
- Dosing note: At 10 mg per unit, two units deliver 20 mg, which sits at the upper end of a moderate starting dose for most consumers.
Example C: concentrate at 650 mg/g
A single gram of concentrate counts as 4 g of dried cannabis toward your public limit. Carry 7.5 g of concentrate and you’ve hit the 30 g ceiling on concentrates alone.
Why labelling precision and dosing caution matter
Label numbers are close, not exact. Health Canada’s precision guidance means a value of 100 mg/g could reflect a tested result anywhere in a rounding window around that figure. For dried flower, that margin is manageable. For edibles and concentrates, where doses are smaller and effects take longer to appear, that variance deserves real attention.
Practical safety points:
- Start with 2.5 mg for edibles if you’re new or returning after a break. Work up to 5–10 mg once you know how your body responds. Consult a healthcare provider if you have questions about appropriate dosing for your situation.
- For inhalation, a single puff of 0.1–0.2 g is a reasonable starting point; wait several minutes before taking more.
- Always check “Total THC per unit” on edibles and capsules, not just the mg/g concentration, since unit mass varies by product.
- Concentrates require extra care. The mg-per-dab numbers in Example C above show how quickly a small mass delivers a large dose.
- Verify your scale. For microdosing at home, a digital scale accurate to 0.01 g is worth the investment. Retail scales must meet Measurement Canada standards, but a home scale may not.
Pro Tip: Keep a note on your phone with the mg/g value and unit mass of your current product. That way you can recalculate mg per serving on the fly without re-reading the label every time.
For more on how Canadian serving sizes map to milligram dosing, the Montrose cannabis serving size guide walks through conservative dosing by product class.
The Montrose perspective on why accurate conversions protect you
At Montrosecannabis, we hear the same question from customers regularly: “How strong is this, really?” The honest answer is that the label tells you everything you need, once you know how to read it. That’s why we put product detail pages front and centre, with unit mass, concentration, and Total THC clearly listed for every item we carry.
We’ve seen what happens when buyers skip the math. Someone picks up a concentrate thinking it’s similar in strength to dried flower, does a dab the size of a typical bowl, and has a very unpleasant evening. The conversion from mg/g to actual milligrams per serving is not a technicality. It’s the difference between a good experience and an overwhelming one.
Our team is available to help you verify unit masses and confirm label details before you order. If a product page ever leaves you uncertain, reach out directly. We’d rather spend two minutes answering a question than have you guess. Compliance and customer education aren’t just brand talking points for us — they’re built into how we select products and how we describe them.
Sources
These are the primary government and public-health references behind this guide:
- Packaging and labelling guide for cannabis products
- Cannabis Legalization and Regulation
- Cannabis Act — section 8
- How to read a cannabis package
- Requirements: scales used for sale of cannabis products — Measurement Canada
- Visual guide to weed weights & measurements
This article is general information, not a substitute for advice from a qualified doctor. Consult a qualified healthcare professional about your own circumstances before acting on anything here.
FAQ
What does “3.5 grams” mean in cannabis slang?
3.5 grams is called an “eighth” — one-eighth of an ounce. It’s the most common purchase size at Canadian cannabis retailers.
How many grams is one ounce of cannabis in Canada?
One ounce is commonly rounded to 28 grams for cannabis transactions in Canada. Retailers and buyers use 28 g as the standard.
How big is 3 grams of cannabis?
3 grams is slightly less than an eighth (3.5 g) and roughly the size of a large grape or a few dense buds, depending on the strain. It typically yields 6–30 individual servings depending on dose size.
How do I convert mg/g on a Canadian label to percent?
Divide the mg/g value by 10. A label showing 150 mg/g Total THC equals 15% THC. This works because mg/g expresses milligrams per 1,000 mg of product, which is the same ratio as percent.
How many grams is 1 cup of cannabis?
A cup is not a standard cannabis measurement and is not used in Canadian retail or regulation. Cannabis is sold and regulated by weight in grams; always use a scale rather than a volume measure for accurate dosing.
