Milligrams vs Percentages: Understanding Cannabis Potency
Last Updated:October, 2026 • Josh
A flower label says 20% THC. A gummy says 5 mg. An oil lists 600 mg in the container. All three numbers describe cannabis potency, but they are answering different questions. Comparing them without checking the units is one reason cannabis can feel confusing before someone even uses it.
You do not need to become a chemist to understand the basics. The useful distinction is between how concentrated a product is and how much of a cannabinoid is in the amount you actually use. Once that clicks, labels become easier to read and strong-looking numbers become less mysterious.
- A percentage describes concentration. Milligrams describe an amount of a particular substance.
- For a concentration stated by weight, 1% equals 10 mg per gram.
- Check whether a number refers to one serving, one piece or the whole container.
- THC content in a product is different from the amount absorbed by your body.
- Potency numbers help with informed choices, but do not establish quality, benefit or a safe personal dose.
What a THC percentage means
A percentage tells you what share of a product is a particular compound. When a cannabis label reports THC as a percentage by weight, 20% means 20 parts THC for every 100 parts of product. In one gram, that works out to 200 mg of THC. It does not mean that every puff delivers 200 mg or that your body absorbs all of it.
Percentage is a concentration, so the amount matters too. A small amount of a highly concentrated product can contain less THC than a larger amount of a less concentrated product. Looking only at the percentage leaves half of the question unanswered.
Our guide to cannabis labels and lab reports explains how to connect a label with a batch-specific certificate of analysis. This article focuses on the numbers themselves.
What milligrams mean
A milligram is a unit of mass. There are 1,000 milligrams in one gram. A label that says a gummy contains 5 mg THC is describing the mass of THC in that gummy, not the weight of the candy. The candy itself may weigh several grams.
The same distinction applies to oils. A bottle containing 600 mg THC does not necessarily contain 600 mg of oil. The oil can include a carrier and other plant compounds. Always read what follows the number: THC, CBD, total cannabinoids or net product weight.
THC and CBD are different compounds. Adding their amounts together can describe total content, but it does not make them interchangeable. A product with 5 mg THC and 20 mg CBD is not equivalent to one with 25 mg THC.
A simple conversion from percentages to milligrams
For a percentage by weight, multiply the percentage number by 10 to get milligrams per gram. Then multiply by the number of grams of product. These examples explain content; they are not suggested amounts to consume.
| Label concentration | Content in one gram | What it describes |
|---|---|---|
| 1% | 10 mg | The named compound per gram of product |
| 10% | 100 mg | The named compound per gram of product |
| 20% | 200 mg | The named compound per gram of product |
For example, 0.1 gram of a product containing 20% THC by weight contains an estimated 20 mg THC. That calculation cannot tell you how much reaches the bloodstream. Inhalation involves losses and variable delivery, while swallowed THC follows a different absorption and metabolism pathway.
Check the basis of the concentration before applying the formula. A liquid labeled in mg/mL requires a volume calculation. A result in mg/g requires a weight calculation. Grams and milliliters cannot be substituted without knowing the product's density.
Per piece, per serving and per package
A package number can look like a serving number at a glance. A container labeled 50 mg THC might hold ten gummies containing 5 mg each. A different container could hold one item containing the full 50 mg. The front of the package may not make that difference obvious.
Before using an edible, find the THC amount per unit, the number of units and the manufacturer's serving information. A single piece can contain multiple labeled servings. Conversely, a labeled serving can consist of more than one small piece.
For a liquid, a label stating 10 mg THC per mL means that 0.5 mL contains 5 mg THC if the product is uniform. It does not mean each drop contains 10 mg. Droppers and pumps vary, so use the product's measurement instructions rather than assuming one squeeze is a known volume.
Why total THC can be a different number
Some flower labels distinguish THC already present from total potential THC, which also accounts for THCA that can convert to THC when heated. Label conventions vary, so read the lab report's definitions instead of assuming every percentage refers to the same measurement.
Total potential THC is a chemistry estimate. It is not a prediction of the amount you will inhale or a guarantee that heating converts and delivers every available molecule. When a report lists both THC and THCA, do not casually add percentages without checking how its total was calculated.
The same number can feel different across methods
Knowing content is useful, but it does not make an edible equivalent to inhaled flower. Timing, absorption, metabolism and individual sensitivity differ. Our article on edible THC and 11-hydroxy-THC explains why swallowing THC can produce an unfamiliar experience.
A potency calculation should never become a reason to take more while waiting. Label numbers cannot establish a universal comfortable amount. A plan for safer use also considers medications, previous experiences, responsibilities and the time available for effects to develop.
Use the number as a starting question
Ask three things: which compound is being measured, what unit is being used and how much product the number refers to. Those questions solve most ordinary label confusion. If the manufacturer cannot clarify the amount or the batch report does not match the product, guessing is not a substitute for reliable information.
Higher THC does not automatically mean better cannabis or better relief. Numbers describe composition. Whether a product fits someone's goals requires a broader conversation about benefits, unwanted effects and daily functioning. Our guide to finding a comfortable starting point continues that conversation.
Sources and further reading
Frequently Asked Questions
No. When stated by weight, 20% equals 200 mg THC per gram of product. The amount in a smaller portion depends on that portion’s weight.
The labeled content may use the same mass unit, but the amount absorbed and the experience can differ by route. Do not treat the two as interchangeable personal doses.
Only if you know the product’s density. Milliliters measure volume and grams measure mass. Use the units given by the manufacturer or lab report.
No. Potency is one part of composition. Testing quality, the actual amount used, other cannabinoids and your goals also matter.
Understanding cannabis potency starts with reading the whole number, including its unit and what it applies to. Percentages explain concentration. Milligrams explain an amount. Neither one can tell you everything about how a product will feel.
At Mercy Leaf, clearer information should make choices less pressured and more thoughtful. You do not need the strongest product or the most impressive label. You need enough reliable information to understand what is in front of you.
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Mercy Leaf Educational Disclaimer
Mercy Leaf provides educational information about cannabis and related topics for informational purposes only. This content is not intended to diagnose, treat, cure, or prevent any disease, and should not be considered medical or legal advice. Cannabis laws vary by jurisdiction, and individual responses to cannabis products may differ. Always consult a qualified professional before making health-related decisions.