Cannabis 101

How to Read Cannabis Product Labels

THC percentages, testing results, and what all those numbers on the packaging actually mean.

By WeedCentral Editorial · 3 min read · Reviewed 2026-Q2

Key takeaways

A higher THC percentage means more intense, not better; many experienced users prefer 18 to 22 percent with rich terpenes.
Total THC equals THC plus 0.877 times THC-A, and that total is the number that predicts psychoactive strength.
Legal cannabis is lab-tested for potency, pesticides, heavy metals, mold and solvents; the label names the lab and batch number.

THC & CBD Percentages

These show the concentration of each cannabinoid. For flower, THC typically ranges from 15-30%. Higher THC doesn't always mean "better": it means more intense. Many experienced users prefer moderate THC (18-22%) with a rich terpene profile over a 30%+ strain that lacks complexity.

Total THC vs. THC-A

Raw cannabis contains THC-A (non-psychoactive), which converts to THC when heated. Labels may show both. The formula: Total THC = THC + (THC-A × 0.877). This "total" number is what matters for predicting psychoactive strength.

Terpene Content

Premium products list terpene percentages. Total terpene content above 2% is considered good, above 4% is excellent. The dominant terpene (highest percentage) is the biggest predictor of the strain's aroma and effects.

Testing & Batch Numbers

Legal cannabis is lab-tested for potency, pesticides, heavy metals, mold, and residual solvents. The label should show the testing lab name and batch/lot number. If a product is recalled, this number identifies affected batches.

Harvest & Package Dates

Freshness matters. For flower, look for a harvest date within the past 3-6 months. Anything over a year old has likely lost significant terpenes. Package date is when the product was sealed: the closer to the harvest date, the better.

Go deeper

Interactive explainer Who keeps cannabis safe? COA rules by country Play one batch from farm to shelf and watch who adds each number to the label, state by state and country by country.

Frequently asked questions

What does the THC percentage on a cannabis label mean?

It shows how concentrated THC is; flower typically ranges from 15-30%. Higher THC means more intense, not necessarily better. Many experienced users prefer moderate THC around 18-22% with a rich terpene profile over a 30%+ strain that lacks complexity.

What is total THC versus THC-A on a label?

Raw cannabis contains non-psychoactive THC-A, which converts to THC when heated. Total THC is calculated as THC plus THC-A times 0.877. That total number is what matters for predicting a product's psychoactive strength, so look for it rather than the THC-A figure alone.

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