How much THCA converts at 240°F for 30 minutes?

With the cannabis already at 240°F (115°C), published kinetics in this calculator give roughly 93–99% THCA converted after 30 minutes, depending on which lab dataset is used. Home trays usually do worse until an oven thermometer confirms the real temperature.

Is 220°F for 60 minutes enough to decarb?

At 220°F (105°C) for 60 minutes, the models here put THCA conversion at about 92–99% and CBDA at about 83%, once the material is actually at temperature. CBD-rich flower often needs longer; try 90 minutes at 220°F or use the chart on the decarboxylation guide for higher heat.

How long to decarb at 250°F?

At 250°F (121°C), about 30 minutes reaches roughly 98–99%+ THCA conversion in the lab models, with CBDA near 98%. Above ~284°F the fit is extrapolated; watch for scorching and terpene loss.

Why does calc420 use 75% decarb efficiency?

The edible calculator reads oven decarb efficiency from config.json (currently 75%) as a conservative planning number for home ovens—tray heat-up, dial error, and uneven piles—not the 90%+ often seen in lab kinetics. Using a lower factor avoids underestimating how strong your edibles might be.

Does CBDA decarb slower than THCA?

Yes. Wang et al. (2016) measured CBDA rate constants about half those of THCA at the same temperature, so CBD flower needs the longer end of the time range at a given heat setting.

Decarb Calculator: % of THCA & CBDA Converted

What your result means

The percentages are the share of THCA or CBDA that turned into THC or CBD under ideal first-order kinetics—not how much ends up in your butter. Wang et al. still measured roughly 8% total loss on the THCA→THC path and about 18% on CBDA→CBD at 110°C in extracts. Terpenes and harsh heat can cost more.

THCA shows a range because two independent lab datasets disagree a little. CBDA uses only Wang’s constants. If the low end of the THCA range is still below ~90%, add time or confirm temperature with a thermometer before infusing.

Quick answers

240°F for 30 minutes?: —
220°F for 60 minutes enough?: —
How long at 250°F?: —
CBDA slower than THCA?: Yes—Wang et al. (2016) measured CBDA rate constants about half those of THCA at the same temperature, so CBD flower needs longer at the same dial setting.
Why 75% in the edible calculator?: —
Dial vs thermometer?: Always trust a thermometer on the middle rack beside the tray. Home dials are often wrong; this tool expects the temperature the cannabis actually sees.
Hotter to save time?: Above ~300°F (149°C) THC can degrade into CBN and you lose terpenes—general kitchen guidance, not from the two kinetics papers here. Stay in the 220–250°F band when you can.

Worked examples (calculator output)

Lab-condition conversions once material is at temperature—not a promise for a thick home tray. For recommended settings, see the decarb temp & time chart.

Setting	THCA (low–high)	CBDA

Lab numbers vs your kitchen

The models often show 90–99%+ conversion while Calc420’s edible calculator plans with 75% oven decarb from config.json. That gap is intentional: trays take time to heat, ovens drift, and piles heat unevenly. For dosing, under-estimating decarb (using 75% when reality is 95%) is the riskier mistake—it makes your edibles look weaker on paper than they are, so people eat more than they should.

If your lab-model estimate is high, you can pass the low end into the edible calculator with “Use my estimate,” or stay conservative with the 75% button. Either way, start with a small test serving.

Get an accurate reading of your oven

Place an oven thermometer on the middle rack next to the tray and preheat until the thermometer stabilizes. Enter that reading above—not only what the dial says. If the dial and thermometer disagree, use the thermometer value every time.

How the calculator works

Decarboxylation is treated as first-order: converted fraction = 1 − e^−k·t, with time in seconds. The rate constant k follows Arrhenius k = A·e^−Ea/(R·T) with T in kelvin and R = 8.314 J/(mol·K).

THCA → THC

Low estimate: Perrotin-Brunel et al. (2011), E_a = 84.8 kJ/mol, A = 3.7×10⁸ s⁻¹ (plant-material study, ~100–140°C).

High estimate: Wang et al. (2016) Table 2 anchor k = 1.83×10⁻³ s⁻¹ at 110°C, E_a = 88 kJ/mol (cannabis extracts, vacuum oven).

CBDA → CBD

Wang et al. (2016) only: k = 0.83×10⁻³ s⁻¹ at 110°C, E_a = 112 kJ/mol. Temperatures above 110°C are extrapolated—shown with a note in the results.

What it doesn’t model

No THC→CBN breakdown curve, no separate kief/hash constants, no tray heat-up delay, and no terpene loss. For kief or hash timing, use the chart page rows and still verify with a thermometer.

Next step: turn the % into mg per serving

Decarb is only step one. Infuse into butter or oil, then split the batch into servings. Use the THC & CBD edibles calculator, the cannabutter ratio chart, or the CBD edibles calculator for CBD-heavy flower. To convert label % to milligrams, see the mg ↔ % tool. Wondering when effects start? Try the onset calculator.

Sources

Perrotin-Brunel H. et al., J. Mol. Struct. 987 (2011) 67–73. doi:10.1016/j.molstruc.2010.11.061
Wang M. et al., Cannabis Cannabinoid Res. 1 (2016) 262–271. doi:10.1089/can.2016.0020 (PMC5549281)

Decarb Calculator: How Much THCA and CBDA Did Your Oven Convert?