The 0.3% THC legal limit works out to 3 milligrams of delta-9 THC per gram of dried hemp on a dry weight basis. That is the bright line in federal law: cannabis at or below 3 mg of delta-9 THC per gram qualifies as hemp and is legal to grow, sell, and ship across state lines; anything above it is marijuana and remains a Schedule I controlled substance. The 2018 Farm Bill wrote that definition into federal agricultural law and simultaneously carved compliant hemp out of the Controlled Substances Act.1Office of the Law Revision Counsel. 7 U.S. Code 1639o – Definitions A significant amendment to that definition takes effect on November 12, 2026, and it changes the milligram math for finished products.
What 0.3% Looks Like in Real Quantities
Percentages feel abstract, so translate them into weight. One gram of dried hemp at the 0.3% limit contains up to 3 milligrams of delta-9 THC. A full ounce, roughly 28 grams, tops out at about 84 milligrams of delta-9 THC spread across the entire amount.
Finished products are where the math gets slippery. Some manufacturers have applied the 0.3% figure to the total weight of the product rather than to plant material alone. Read that way, a 5-gram gummy can legally contain up to 15 milligrams of delta-9 THC and still come in at 0.3% by weight. Fifteen milligrams is a meaningful psychoactive dose, comparable to servings sold in regulated dispensaries. Same percentage, very different product.
Can 0.3% THC Actually Get You High?
Raw hemp flower at 0.3% THC will not produce a noticeable high for most people. Research suggests cannabis generally needs to reach around 1% THC before it produces meaningful psychoactive effects, and 0.3% sits at roughly a third of that.2PMC. Practical Considerations in Medical Cannabis Administration and Dosing Someone unusually sensitive might feel a subtle relaxation, but that is the ceiling.
Concentrated products behave differently. A hemp-derived edible engineered to deliver 5, 10, or 15 milligrams of delta-9 THC per serving under the dry-weight reading of the rule will produce real intoxication even though its label can still claim “hemp.” Read the milligram figure, not the marketing.
Hemp Products and Drug Tests
Legal hemp can still trigger a positive workplace drug screen. Standard immunoassay tests flag THC-COOH, the metabolite the body produces from any delta-9 THC, at 50 nanograms per milliliter. Confirmatory gas chromatography-mass spectrometry testing often uses a 15 ng/mL cutoff.3PMC. Cannabidiol (CBD) Product Contamination: Quantitative Analysis of Delta-9-Tetrahydrocannabinol Concentrations Found in Commercially Available CBD Products
Regular use of full-spectrum CBD products can accumulate enough metabolite to cross those thresholds. One study found that daily doses as low as 0.4 milligrams of delta-9 THC could produce a positive result, and detected delta-9 THC in five of 21 products labeled “THC Free,” with concentrations up to 0.656 milligrams per milliliter.3PMC. Cannabidiol (CBD) Product Contamination: Quantitative Analysis of Delta-9-Tetrahydrocannabinol Concentrations Found in Commercially Available CBD Products A drug test does not distinguish between metabolites from a legal hemp gummy and any other source.
How the 0.3% Is Measured
Federal rules do not measure only the delta-9 THC already present in a sample. Labs must also account for THCA, a non-intoxicating precursor that converts to active THC when heated. When the testing method preserves THCA rather than converting it, the lab applies a formula: total THC equals delta-9 THC plus 87.7% of the THCA content.4eCFR. 7 CFR 990.1 – Meaning of Terms The 87.7% factor accounts for molecular weight lost during conversion. Testing must use post-decarboxylation methods or an equivalent approach that captures the conversion, with results reported on a dry weight basis.5eCFR. 7 CFR 990.25 – Standards of Performance for Detecting Total Delta-9 Tetrahydrocannabinol Concentration Levels
The practical consequence: a plant can test at 0.2% delta-9 THC and still fail the limit once its THCA is counted. Two lab techniques are approved for compliance testing: High-Performance Liquid Chromatography, which preserves the acidic forms, and Gas Chromatography, which heats the sample and converts THCA into active THC during analysis.6eCFR. 7 CFR Part 990 – Domestic Hemp Production Program
Reading a Certificate of Analysis
For consumers, the Certificate of Analysis is the practical check on what a product actually contains. A reliable COA comes from an independent, ISO 17025-accredited lab and shows the full cannabinoid profile with exact THC and CBD levels, batch identification, testing date, methodology, and screening results for heavy metals, pesticides, and residual solvents. Many states now require a scannable QR code on the label that links to the COA. If the lab results are not easy to find, buy elsewhere.
The November 2026 Change to the Milligram Rule
Congress amended the federal definition of hemp in November 2025 as part of H.R. 5371, a continuing resolution to fund the federal government.7Congress.gov. H.R. 5371 – 119th Congress – Continuing Appropriations and Extensions for Fiscal Year 2026 The changes take effect on November 12, 2026, and they reshape how the milligram math works.
- The 0.3% limit will apply to total THC rather than delta-9 THC alone. Total THC includes THCA, delta-8 THC, and other tetrahydrocannabinols. Products that stayed compliant by concentrating THC variants other than delta-9 will no longer qualify.
- Finished hemp-derived cannabinoid products cannot contain more than 0.4 milligrams of total THC per container. That per-container cap closes the dry-weight loophole that let heavy gummies carry 10 or 15 milligrams under the old reading.
- Synthesized cannabinoids are excluded. Delta-8 THC produced by chemical conversion of CBD, and substances not naturally occurring in cannabis, will no longer meet the definition of hemp regardless of their percentage.
The scope is broad. Hemp-derived delta-8 gummies, THCA flower marketed as a legal alternative to marijuana, high-dose delta-9 edibles sold under the dry-weight reading, and products containing HHC or THC-O all fall outside the amended definition. Anything that does not meet the new standard is marijuana under the Controlled Substances Act, with the same federal consequences as any other Schedule I substance. If you buy or sell hemp-derived products with noticeable psychoactive effects, November 12, 2026 is the date the milligram math changes underneath you.