Distillate cart potency: the short answer
Potency is the THC concentration in the oil inside a cartridge. Legal distillate carts in the U.S. test between 70% and 90% THC by weight. A 1-gram cart labeled 80% THC holds about 800 mg of THC. That figure describes the oil. It does not describe the dose a person inhales in one puff.
What the lab measures
Testing labs use high-performance liquid chromatography (HPLC). The report lists delta-9 THC, THCA, total THC, CBD, CBN, and total cannabinoids.
Total THC follows one formula: total THC = delta-9 THC + (THCA x 0.877). The 0.877 factor accounts for the mass lost when THCA converts to THC. Distillate holds small amounts of THCA because heat during refinement drives that conversion.
Why potency varies from batch to batch
- Cultivar and starting material. Trim and flower differ in cannabinoid content.
- Refinement steps. Each pass through the distillation rig removes more non-THC material and raises the percentage.
- Additives. Terpenes, botanical flavors, and diluents can make up 5% to 15% of the final oil, which lowers THC per gram.
- Batch size. Small runs hold a tighter range than large runs.
What does not change the label
The device sits outside the test. A lab tests oil from a jar, not vapor from a coil. Coil temperature, airflow, and draw length set the inhaled dose.
Published work on cannabis vaporizers shows that a 3-second draw at low voltage releases a fraction of the THC in the oil. High voltage raises the yield and also raises the count of degradation products. The label cannot predict that split.
Label rules and tolerance
Washington requires the THC value on a cannabis label to fall within 10% of the value from the compliance test. A cart that tests at 82% THC can carry a label between 74% and 90%. Read the test date and the batch number before you compare two products.
What potency does not cover
A potency test covers cannabinoids. It does not cover pesticides, residual solvents, heavy metals, or microbials. Those results appear on separate panels. A cart with 88% THC and a failed solvent test is still a failed product.
How to compare two carts at the counter
- Check total THC, not delta-9 THC alone.
- Check the gram weight. A 0.5-gram cart at 90% holds 450 mg of THC, less than a 1-gram cart at 60%.
- Check the test date.
- Check the ingredient list for additives.
Convenience and the percentage on the box
Cartridges sell as a convenience format: no grinding, no rolling, no open flame. With the format settled, the percentage becomes the number shoppers compare. Two carts from the same brand in the same hardware get sorted by THC. That comparison ignores temperature settings, puff size, and the additives listed above. Potency is one input. It is not the dose.