Potency on a cannabis label means THC content. Flower and concentrates list a percentage. Edibles list milligrams. A flower label of 20% THC means 200 mg of THC in 1 gram of dried plant. Legal states require labels to show total THC, not just delta-9 THC.
How Total THC Is Calculated
Raw cannabis holds most of its THC as THCA, an acid form that does not intoxicate. Heat converts THCA to THC. Labs report both numbers, and the total follows one formula:
Total THC = delta-9 THC + (THCA x 0.877)
Cannabis Potency Chart by Type: THC Ranges for Flower, Vapes, Edibles and Concentrates
The 0.877 factor accounts for the carboxyl group lost during decarboxylation and the drop in molecular weight. A sample with 20% THCA and 1% delta-9 THC tests at about 18.5% total THC.
Flower Potency Ranges
- Low: 10% to 15% total THC. Common in older cultivars and CBD-leaning types.
- Middle: 15% to 22%.
- High: 22% to 30%.
Federal monitoring of seized cannabis samples in the 1990s reported averages under 5% THC. State tracking data from recent years puts retail flower near 20% to 25% in several markets. A higher number does not mean a proportionate change in effect.
Concentrates
- Hash and kief: 20% to 50% THC.
- Live resin, wax, shatter, rosin: 60% to 90% THC.
- Distillate vape cartridges: 70% to 95% THC.
One 0.5 g dab at 80% THC holds about 400 mg of THC. That is 40 times a standard 10 mg edible serving.
Edibles and Milligrams
Most legal states cap a single serving at 10 mg THC and a package at 100 mg. Washington and Colorado use that 10 mg serving standard. Some states allow 5 mg servings.
Oral THC passes through the liver before it reaches blood. Reported oral bioavailability runs about 4% to 20%. Reported inhaled bioavailability from smoke or vapor runs about 10% to 35%. Onset takes 30 to 120 minutes for edibles and 5 to 15 minutes for inhaled products.
What the Percentage Does Not Show
Lab variance. Studies of state-licensed labs report differences of several percentage points between labs on the same sample. A 25% label can test at 21% at another lab.
Dose. Weight of product matters as much as percent. 0.1 g of 25% flower holds about 25 mg THC. 0.1 g of 15% flower holds about 15 mg. Inhaled use transfers a fraction of that dose.
Tolerance. Repeat use changes CB1 receptor density. Daily users report less effect at the same dose. A break of 1 to 2 weeks reduces tolerance for many people.
Terpenes. These compounds sit at 1% to 3% of flower weight. They shape smell and taste. Human research on how they alter THC effects is limited.
How to Read a Label
- Find total THC. THCA alone is not the total.
- Note the package weight or the serving count.
- For edibles, read mg per serving and servings per package.
- Check the harvest date and the test date.
- Ask the dispensary for the batch lab report.
Dosing Notes
Start low. 2.5 mg to 5 mg THC is a common first edible dose. Wait two hours before a second dose. Inhaled effects peak in 10 to 30 minutes. High-THC concentrates raise tolerance faster than flower for many users.