Total THC is the predicted final concentration of psychoactive Δ9 THC in a cannabis sample after complete decarboxylation. It's a calculated value, not a direct measurement. Formula: Total THC = Δ9 THC (%) + (0.877 × THCa %). The 0.877 multiplier accounts for the mass lost during decarboxylation (THCa loses a carboxyl group, which accounts for ~12.3% of its molecular weight). Example: a flower testing with Δ9: 0.21% and THCa: 27.8% has Total THC = 0.21 + (0.877 × 27.8) = 24.6%. Total THC is what consumers experience when they smoke or vape — the Δ9 number on the COA is the raw reading before any heat. Total THC is also what the proposed Section 781 federal threshold uses (post-November 12, 2026), replacing the current Δ9-only standard from the 2018 Farm Bill.
Entering the team…
