How to Read a Cannabis Label: THC, CBD, and Dosing Explained
Learn how to read a cannabis label: total THC vs. THCA, milligrams per serving, terpenes, batch numbers, and COAs, so you know the dose before you buy.
Quick answer
A percentage on a cannabis label tells you how much THC or CBD is present by weight. If flower is labeled 20% THC, one gram of that flower holds roughly 200 mg of THC. A 10 mg edible is a different format: the number is a fixed dose per serving, not a percentage. To read any label correctly, use the "Total THC" and "Total CBD" lines, then check the net weight or serving size before you do the math.
Before you start
- A product label with a full cannabinoid panel
- The net weight in grams or the servings per package
- A calculator or phone
How to read the numbers step by step
- Find the cannabinoid panel, usually a small table listing THCA, delta-9 THC, Total THC, CBDA, CBD, and Total CBD.
- Read the "Total THC" row, not the raw THCA row. Labs calculate total THC as THCA multiplied by 0.877 plus the active delta-9 THC.
- Read the "Total CBD" row the same way, using CBDA multiplied by 0.877 plus CBD.
- Locate the net weight or serving size. Flower and concentrates list grams. Edibles list milligrams per serving and total servings per package.
- Convert the percentage to milligrams by multiplying the weight in grams by 1000, then multiplying by the percentage written as a decimal.
- Divide by the number of servings if you are using an edible, tincture, or beverage.
- Check the batch date and the lab name to confirm the sample matches the package you are holding.
- Compare the THC number to the CBD number to see the actual ratio, such as 1:1 or 20:1.
What the percentages mean in practice
Percentages describe concentration, not total strength. A 30% THC pre-roll and a 15% THC pre-roll can hold the same total THC if the second one is twice as heavy. This is why a 1 gram joint at 18% THC delivers about 180 mg of THC, while a 0.5 gram joint at 32% THC delivers about 160 mg. Weight matters as much as the headline number.
how to read a cannabis concentrate label
Concentration also does not translate directly into effect. Inhaled THC reaches the bloodstream within minutes, while swallowed THC passes through the liver and produces a slower, longer, and often stronger result. A 5 mg edible can feel closer to 15 mg of smoked flower for some people.
How to Read Cannabis Edible Labels for Dosage
Typical potency ranges
- Flower: 15% to 30% total THC in most licensed markets
- Pre-rolls: 15% to 35% total THC
- Concentrates and vape cartridges: 60% to 90% total THC
- Tinctures: 1 mg to 5 mg per drop, or a listed mg per mL
- Edibles: 1 mg to 10 mg THC per serving in most states
- CBD-dominant products: 10% to 50% total CBD on average
Hemp versus cannabis labels
Hemp products must stay at or below 0.3% delta-9 THC by dry weight under federal law, so a hemp label can show a large CBD percentage and a very small THC number. Cannabis products sold in state-licensed dispensaries carry no such ceiling and often list total THC well above 0.3%. Read the delta-9 THC line separately from total THC, because the two are not the same figure on hemp paperwork.
How to Interpret Cannabis Expiration Dates
Common label mistakes
- Confusing THCA with total THC. Raw THCA is not psychoactive until it is heated.
- Treating a milligram dose as a percentage. A 10 mg gummy is not 10% THC.
- Assuming a higher percentage always hits harder. Tolerance, body weight, and method of use all change the outcome.
- Ignoring serving size. One package can contain 20 servings at 10 mg each.
- Trusting the strain name over the lab panel. Names carry no legal potency meaning.
Start at 1 mg to 2.5 mg of THC if you are new, wait at least two hours before adding more with edibles, and keep the label so you can repeat or avoid the same dose next time.