Decarb Calculator

How this decarb calculator works

Decarboxylation follows first-order kinetics, which means the percentage of acid left depends on a single number per temperature: the rate constant. The conversion card computes 1 − e^(−k·t), where k comes from an Arrhenius fit of the three values measured by Wang et al. (2016) in Cannabis and Cannabinoid Research - 0.18, 0.66, and 1.83 ×10⁻³ s⁻¹ for THCA-A at 80, 95, and 110°C. Between those points the fit is interpolation; the 99%-time the widget prints at 110°C (~41 min) reproduces the paper's own statement that THCA-A "approached zero" in 30 minutes to within a few minutes, so the same arithmetic stays trustworthy a little beyond 110°C.

The milligram card is the dosing arithmetic: grams × lab percent × 1,000 gives the starting milligrams of acid, the conversion percentage decides how much reacts, and 0.877 converts acid mass to neutral mass (the carboxyl group leaves as CO2). The result is a ceiling - nothing home-side ever beats it. And when the next question is "how strong per tablespoon of butter, or per cookie?", the cannabutter dosage calculator carries this same math into the batch.

What the four verdicts mean

• Under-converted - under 90% of the acid has reacted. Edibles made from this plan land weaker than the lab report suggests.
• Mostly converted - 90-99%. Fine in practice, but the last stretch is cheap: add time.
• Conversion complete - 99%+ converted. The plan has reached its ceiling.
• Past complete - you are now spending THC, not making it: degradation toward CBN and volatile loss both scale with time past the endpoint.

Limits of the estimate

The cited kinetics come from cannabis extracts in a vacuum oven. Your kitchen differs in four ways the sliders cannot encode: starting material already carries partially converted acid from drying and storage; moisture buffers the temperature at the material; layer thickness means the top and bottom of the tray see different heat; and a home oven cycles 10-25°F around its set point. That last one is why the machine exists at all - a preset cycle is the only way to make the calculator's assumption true. And treat any potency this page outputs as an upper bound: the FDA's 2022 advisory on THC food products exists because edibles whose strength nobody controls are a documented consumer-safety problem; dose conservatively and keep finished material out of reach of children.

Decarb calculator questions