A THC percentage tells you how much THC the product contains by weight. A cannabis flower labeled 20% THC holds about 200 mg of THC in every gram of plant material. The number describes the chemical makeup of the product. It does not tell you the dose you should take, and it does not predict how strong the effect will feel for you.
What the Percentage Is Comparing
Labs measure THC as a share of the sample weight. One gram equals 1,000 milligrams, so 1% THC equals 10 mg per gram. If a producer reports 15% THC, that batch contains roughly 150 mg of THC per gram of material. The same math applies to oils, edibles, and concentrates, but the weight used in the calculation changes with the product type. Concentrates often test between 70% and 90%, while hemp flower sold for CBD sits near or below 0.3%.
How to Read a THC Percentage on a Label
- Locate the cannabinoid panel on the package or on the batch certificate of analysis.
- Check which value is listed: THCA alone, THC alone, or total THC.
- Write down the net weight of the package in grams.
- Multiply the percentage by 10 to convert it to milligrams per gram.
- Multiply that figure by the total grams to get the THC content in the whole package.
THCA, THC, and Total THC
Raw cannabis holds most of its THC in the acidic form called THCA. THCA does not produce intoxication on its own. Heat drives a reaction called decarboxylation that turns THCA into THC, which is why smoking, vaping, and baking activate the plant. Labs report both values plus a total. Total THC equals THC plus THCA multiplied by 0.877, since the conversion sheds part of the molecule as carbon dioxide.
Why Percentage and Milligrams Are Not the Same
Percentage depends on weight, so a small heavy item and a large light item can carry the same percentage and very different doses. A 1 gram cartridge at 80% THC holds 800 mg of THC. A 5 gram gummy at 2% THC holds 100 mg. The cartridge shows the larger percentage. The gummy delivers a measured dose per piece. Edibles are labeled in milligrams per serving for this reason.
Higher Percentage Does Not Mean a Better Fit
Inhaled THC reaches the bloodstream in minutes. Eaten THC passes through the liver and arrives slower, with effects that can last longer. Tolerance, body weight, and frequency of use shift the response. A person can take two puffs of 18% flower and feel more than a single puff of 28% flower. Dose, method, and setting drive the experience more than the percentage alone.
THC Percentage in Hemp and CBD Products
Hemp is defined in US federal law as cannabis with no more than 0.3% THC on a dry weight basis. Full-spectrum CBD oil from hemp can carry trace THC, while broad-spectrum and isolate products are processed to remove it. Labels may read ND for not detected. Open the batch certificate of analysis and confirm the THC result matches the claim on the package.
Quick Reference
- 1% THC equals 10 mg of THC per gram of product.
- Total THC equals THC plus THCA times 0.877.
- The federal hemp limit is 0.3% THC on a dry weight basis.
- Edible doses appear in milligrams per serving, not percent.