Cannabis Decarboxylation Temperature and Time Chart

For dry cannabis flower in a home oven, the usual setting is 115C (239F) for 40 to 50 minutes. In a laboratory study on cannabis extract, THCA was almost entirely converted to THC after 30 minutes at 110C, 9 minutes at 130C and 6 minutes at 145C [1]. Flower heats more slowly than a thin film of extract, which is why the home times below are longer than the lab times. The full chart follows.

This page is the numbers. For the step-by-step method, the chemistry and the common mistakes, read how to decarb weed, the full decarboxylation guide. For a water bath instead of an oven, see sous vide decarboxylation.

The main decarboxylation chart

Temperatures are oven air temperature measured with a thermometer, not the dial setting. The suggested times are starting points for coarse ground dry flower in a single layer. The right-hand column is what published research measured, so you can see how far the advice is from the evidence.

Temperature	Suggested time for flower	What research measured	Use
95C (203F)	90 to 120 min	In extract, the measured rate means half the THCA converts in about 18 minutes; conversion was still running at 60 minutes [1]	Sous vide and other water-bath methods
100C (212F)	90 to 120 min	Below 100C the reaction did not finish within 60 minutes in extract [1]. A review estimates about 3 hours for full conversion at 100C [5]	Slow and gentle, when time is not a concern
110C (230F)	50 to 70 min	THCA in extract approached zero after 30 minutes [1]	A safe choice if your oven runs hot
115C (239F)	40 to 50 min	Not tested directly; it lies between the 110C and 130C results [1]	The standard home setting
120C (248F)	30 to 40 min	A study on flower used 30 minutes at 120C and kept it that short to limit the loss of volatile terpenes [4]	Butter and oil infusions
130C (266F)	20 to 30 min	THCA in extract approached zero after 9 minutes [1]	Faster, with more aroma lost
145C (293F)	15 to 20 min	THCA approached zero after 6 minutes in extract. An earlier study found THC peaked at 5 to 10 minutes and then fell [1]	Not recommended
160C (320F)	Not recommended	Pure THCA was fully converted within 15 minutes, and CBN began to appear [1]	Avoid

These are practical ranges, not lab constants. The laboratory figures come from extract heated in a vacuum oven, not from buds on a tray, and published work disagrees on exact times. Moisture, particle size and how the material was stored all shift the result. Treat every time as a starting point for your own oven.

The ceiling nobody can beat: about 87.7%. Decarboxylation removes a carboxyl group, which leaves as carbon dioxide. THCA weighs 358.5 g/mol and THC 314.5 g/mol [2][3], so 1000mg of pure THCA can only ever become about 877mg of THC. Any calculator claiming 1:1 is wrong. Our potency calculator applies the 0.877 factor, and how to calculate the potency of homemade edibles shows the arithmetic.

Decarb settings by material and form

No study has measured these forms side by side, so the rows below are starting settings, not results. Denser and wetter material needs longer; finer material heats faster and scorches sooner. Judge the finish by the signs described further down.

Material	Temperature	Starting time	Notes
Whole buds, unbroken	115C (239F)	55 to 70 min	Heat reaches the core slowly. Break buds apart instead if you can
Coarse ground flower	115C (239F)	40 to 50 min	The standard. Pieces roughly rice-sized
Fine ground flower	110C (230F)	25 to 35 min	Large surface area heats fast. A lower temperature avoids scorching
Kief	105C (221F)	20 to 30 min	Fine and resinous, it burns easily. Watch it and stir once
Hash, pressed	110C (230F)	30 to 45 min	Break it up first. Pressed hash heats unevenly
Trim and sugar leaf	115C (239F)	40 to 50 min	Less cannabinoid content, same chemistry
Fresh or damp material	Dry it first	Until it crumbles	Water must evaporate before the material can rise much above 100C

Method comparison

Method	Temperature control	Smell	Effort
Oven, open tray	Poor. Ovens cycle above and below the set point [7]	Strong, fills the house	Low
Oven, closed jar	The same oven, with the glass slowing the swings	Reduced while the jar stays shut	Low, but the jar heats more slowly
Sous vide, sealed bag	Very good, but capped by boiling water	Almost none until the bag is opened	Medium. Needs a circulator and a bag
Dedicated decarb device	Good. Preset cycles, closed chamber	Low	Lowest. One button

A water bath tops out at the boiling point of water, about 100C (212F) at sea level, so it needs 90 minutes or more. It is the most even option and the slowest. Terpenes are volatile and leave with heat, which is why researchers keep the heating step short when aroma matters [4]. No controlled study compares terpene retention across these four methods, so treat any claim that one keeps more aroma as an expectation, not a measurement.

What temperature should I decarb cannabis at?

115C (239F) for 40 to 50 minutes is the common home setting for dry flower. If your oven is known to run hot, set 110C (230F) and add ten minutes. Both sit between temperatures where laboratory conversion was close to complete in 30 minutes or less [1].

How long does decarboxylation take?

40 to 50 minutes at 115C (239F) for coarse ground flower. Lower temperatures need longer: below 100C the reaction did not finish within an hour in the laboratory [1]. Higher temperatures are faster and cost you aroma first, then THC.

What happens if you decarb too hot?

THC itself starts to break down. In earlier work cited by the same laboratory, THC peaked after 5 to 10 minutes at 145C and then fell, and at 160C CBN began to appear [1]. CBN is a different cannabinoid, not a stronger form of THC, and claims that it is a sleep aid rest on small, dated studies [6]. If a batch came out weak and smelled scorched, overheating is a likely cause. CBN, the hidden gem of the cannabinoids covers what is known about it.

What happens if you decarb too cold?

The reaction runs slowly. In the laboratory, at 80C and 95C, conversion was still incomplete after 60 minutes [1]. You end up with a mix of THCA and THC and a weak batch. This is one of the causes covered in why edibles do not work for me.

Does grinding change decarb time?

Yes. Smaller pieces heat through faster, so they finish sooner and scorch sooner. Grind to roughly rice-sized pieces: powder burns at the edges, and whole buds keep a cool core.

How do you know when decarb is done?

Properly decarbed flower is dry, crumbles between your fingers rather than compressing, and has turned from green to a light toasted brown. The smell shifts from grassy to nutty. Colour alone is unreliable, since strains darken at different rates. Use all three signs.

About your oven

Ovens do not hold one temperature. The element switches on and off, so the air cycles above and below the set point, and the dial can be off as well [7]. Put an oven thermometer on the middle shelf, watch it for twenty minutes, and correct the dial by the average you measure. This check matters more than any number in the chart above.

Once decarbed, the material goes into fat. The best oils for cannabis infusion covers which to choose. When decarboxylated rosin or full-spectrum oil is formulated for vaporization rather than edibles, preserving volatile monoterpenes requires low-voltage ceramic and full-zirconia 510 cartridges regulated between 1.8 V and 2.2 V so coil surface temperatures stay below the 185 C terpene scorching threshold.

Frequently asked questions about decarb temperature

What is the best temperature to decarb cannabis?

115C (239F) for 40 to 50 minutes is the common home setting for dry flower. In laboratory tests on extract, THCA was almost fully converted after 30 minutes at 110C [1]; the longer time allows for flower heating more slowly.

Can you decarb at 120C (248F)?

Yes. 30 to 40 minutes at 120C (248F) works and is a little faster. Expect more aroma loss, since terpenes are volatile [4].

How much THC do you get from THCA?

At most about 87.7% by mass. The carboxyl group leaves as carbon dioxide, so 1000mg of THCA yields roughly 877mg of THC [2][3].

What temperature destroys THC?

Losses start when you go well above the decarb range. THC peaked and then fell at 145C, and CBN appeared at 160C [1].

Is longer at a lower temperature better?

For aroma, it is the usual advice, because heat drives terpenes off [4]. Go too low, though, and conversion stays incomplete: below 100C it did not finish within an hour in the laboratory [1].

How do I know my oven is accurate?

Assume it is not. Ovens cycle around the set point [7]. Use a separate oven thermometer on the middle shelf and read it over twenty minutes.

Sources

1. Wang M, Wang Y-H, Avula B, et al. Decarboxylation Study of Acidic Cannabinoids: A Novel Approach Using Ultra-High-Performance Supercritical Fluid Chromatography/Photodiode Array-Mass Spectrometry. Cannabis and Cannabinoid Research. 2016;1(1):262-271. doi:10.1089/can.2016.0020
2. PubChem. Tetrahydrocannabinolic acid, CID 98523. National Library of Medicine. pubchem.ncbi.nlm.nih.gov/compound/98523
3. PubChem. Tetrahydrocannabinol, CID 16078. National Library of Medicine. pubchem.ncbi.nlm.nih.gov/compound/16078
4. Boffa L, Binello A, Cravotto G. Efficient Capture of Cannabis Terpenes in Olive Oil during Microwave-Assisted Cannabinoid Decarboxylation. Molecules. 2024;29(4):899. doi:10.3390/molecules29040899
5. Iffland K, Carus M, Grotenhermen F. Decarboxylation of Tetrahydrocannabinolic acid (THCA) to active THC. European Industrial Hemp Association / nova-Institut, 2016 (a review; its times are read from a trendline over earlier studies). PDF
6. Corroon J. Cannabinol and Sleep: Separating Fact from Fiction. Cannabis and Cannabinoid Research. 2021;6(5):366-371. doi:10.1089/can.2021.0006
7. Sub-Zero Group (Wolf). Oven temperature issue. subzero-wolf.com

Equipment for decarboxylation and infusion at home: the NOIDS Basic Bundle.