How to Calculate THC in Homemade Edibles

To calculate THC in homemade edibles, multiply grams of flower by the THC percentage (as a decimal) and by 1,000 to get total potential THC, then apply the 0.877 decarboxylation factor and an infusion efficiency between 0.6 and 0.8. Divide by the number of portions to get the per-serving dose — New York caps a single adult-use serving at 10 mg THC.

Why does THC math matter for homemade edibles?

Homemade edibles vary wildly from piece to piece, because every batch is left to home math and kitchen variability. Underestimating potency leads to accidental overconsumption — the most common scenario with homemade infusions — and overestimating it wastes a batch of butter, oil, or flour that took hours to make.

The basic case for knowing the math is safety: if you can calculate the THC in your recipe, you can stay in control of the dose.

Key reasons to run the numbers before baking:

Underestimating potency is the most common cause of accidental overconsumption.
Overestimating potency wastes a batch of butter, oil, or flour.
New York State caps a single adult-use serving at 10 mg of THC, with a maximum of 100 mg per package [6].
Hitting the 10 mg target reliably requires doing the math before the recipe hits the oven.

How THC and CBD Work sets the broader stage for how THC moves through the body, which informs why oral dosing behaves so differently from inhalation. Once the math is part of the process, homemade edibles stop being a guessing game and become a controlled ingredient in a recipe — the same way a measured cup of flour is.

How much THC is in one gram of cannabis flower?

Every dosing calculation starts with one number: the total potential THC in the starting material. That number is set by the percentage on the label and the weight in grams. The conversion is straightforward — multiply grams by the THC percentage (as a decimal) and then by 1,000 to get milligrams.

Worked examples at common potencies:

1 gram of flower at 20% THC = 1 × 0.20 × 1,000 = 200 mg of potential THC.
1 gram of flower at 25% THC = 1 × 0.25 × 1,000 = 250 mg of potential THC.
1 gram of flower at 28% THC = 1 × 0.28 × 1,000 = 280 mg of potential THC.
7 grams of flower at 20% THC = 7 × 0.20 × 1,000 = 1,400 mg of potential THC.

How Long Does Weed Stay Fresh? walks through how flower potency degrades over time, which becomes relevant for any home recipe that uses older stock and tries to back-calculate potency from a label that's no longer current. The dispensary label on a sealed eighth is the best starting point; without it, every downstream step is guesswork and the math collapses before it starts.

What is the 0.877 decarboxylation conversion factor?

Raw cannabis flower contains mostly THCA, not active THC. Heat converts THCA to THC, but the two molecules are not 1:1 by mass — the molar-mass ratio gives the 0.877 conversion factor that any homemade-edible calculation has to apply [3]. Skipping this step overestimates potency by roughly 12–15%, which is the difference between a 10 mg cookie and a 12 mg cookie at the recipe stage.

The standard decarboxylation step runs at 220–240°F for 30–60 minutes [7]. Going below that window leaves too much THCA behind and inflates the "potential" number while cutting actual dose; going above risks burning the THC off as vapor and leaves the finished batch weak. An oven thermometer is worth the drawer space because most home ovens drift 20°F or more from what the dial reads.

Why the 0.877 factor is non-optional:

Raw flower is mostly THCA, not active THC — heating converts THCA to THC by mass loss.
The molar-mass ratio of THCA to THC is 358.47 g/mol to 314.47 g/mol, giving 0.877.
Skipping the factor overestimates potency by roughly 12–15% in a typical batch.

Applied to the worked numbers above:

200 mg potential THC × 0.877 = 175 mg activated THC.
1,400 mg potential THC × 0.877 = 1,228 mg activated THC.

Infographic 1

THC Beverages: A Buyer’s Guide to Dosing, Onset, and Effects applies similar dosing math to infused drinks, where serving size and onset shift the same 0.877 figure into a different format.

How do you factor in infusion efficiency?

No home extraction pulls 100% of the available THC into butter, oil, or alcohol. Some of it stays trapped in plant material, some is lost to heat degradation, and some clings to the sides of the pot rather than transferring into the fat. Typical home infusion efficiency runs 60–80% depending on the starting material, the fat used, time, and temperature, with 70% (0.7) being a reasonable middle-of-the-road assumption for a standard cannabutter or coconut-oil infusion.

Applied to the decarbed number above:

175 mg activated THC × 0.70 = 122 mg of THC in the infusion.
1,228 mg activated THC × 0.70 = 860 mg of THC across a 7-gram batch.

The fully assembled formula is now:

Total THC mg = grams × THC % (decimal) × 1,000 × 0.877 × infusion efficiency

For 7 grams of flower at 20% THC with 70% infusion efficiency, that produces roughly 860 mg of activated THC across the whole batch [1].

Oil Topicals covers a related infusion format — oil-based topicals — where the same fat-soluble principles apply but the route of administration changes the dosing math entirely.

How do you calculate the dose per serving?

Once the total THC in the batch is known, the dose per serving is a division problem: total THC divided by the number of portions actually cut. The number of portions is itself a variable, which is why two batches from the same recipe can produce different doses simply because one was cut into 20 cookies and the other into 35.

Worked examples, all from a 350 mg total THC batch (a smaller 5-gram batch at 20% with 70% efficiency):

350 mg ÷ 20 cookies = 17.5 mg per cookie.
350 mg ÷ 35 cookies = 10.0 mg per cookie — a clean per-dose match to the New York adult-use serving cap [6].
350 mg ÷ 50 cookies = 7.0 mg per cookie — a sensible beginner dose.

Why weighing beats eyeballing:

Visual portioning routinely varies by 30–50% between pieces from the same pan.
The math is trying to control exactly this kind of variability.
Weighing each piece after cutting closes the gap that visual estimates open up.

The reliable approach is to weigh each piece on a kitchen scale after cutting. Total THC ÷ actual gram weight of a piece × (pieces in batch / 1) is the most accurate way to handle uneven cuts, but the simpler "divide total by portions" rule is good enough for most home cooks as long as cuts are consistent.

How long do homemade edibles take to kick in?

Connect the dosing math to the timing, and the dosing conversation becomes complete. Pharmacokinetic studies show oral THC becomes detectable in the bloodstream within 30 to 60 minutes after eating, with peak blood levels typically between 1.5 and 3 hours [4][2]. A 10 mg dose in a commercial edible produces a measured Tmax of 35–90 minutes across study participants, and homemade pieces follow a similar curve, give or take the variability built into any home math.

Onset, peak, and duration at a glance:

Onset: 30–60 minutes for oral THC to become detectable.
Peak: 1.5–3 hours after eating, with Tmax of 35–90 minutes in study participants.
Duration: 6–8 hours for most consumers — much longer than inhalation [5].
Re-dose rule: wait at least two full hours before taking more.

The practical rule holds regardless of the exact number: wait at least two full hours before re-dosing. A second dose on top of an in-progress first dose is the most common overconsumption pattern with homemade edibles, and it almost always traces back to impatience rather than miscalculation. Edibles walks through the same onset and duration story for Treehouse's lab-tested Edibles selection, where the dose is known and the timing curve is the same.

Why are homemade edibles less reliable than store-bought?

Commercial edibles are lab-tested for exact THC content and homogenized so each piece in a batch is uniform. A 10 mg gummy in a regulated package contains 10 mg ±5%, because the manufacturer ran the same math the recipe above does — but in a controlled facility with verified input potency, certified infusion efficiency, and piece-level quality checks. Gummies Edibles covers the gummies subcategory specifically, where the dose-on-the-label expectation is the entire point of the format. For a starting option in the lab-tested lineup, give customers a measured, predictable alternative that removes the dosing math from the equation entirely.

Where homemade and lab-tested diverge:

Dose accuracy: homemade pieces can vary by 30–50% piece to piece; lab-tested pieces land within ±5% of the label.
Mixing: homemade relies on hand-stirred batter or butter; lab-tested uses industrial homogenization.
Decarboxylation: home ovens drift 20°F or more from the dial; commercial lines hold a tight ±5°F window.
Quality checks: commercial pieces are spot-checked per batch; homemade has no independent verification step.

Infographic 2

Homemade versions rely on home math, uneven decarboxylation, and imperfect mixing. The exact same recipe can produce a 5 mg brownie and a 25 mg brownie from the same pan, simply because one absorbed more butter than the other. That variability is not a flaw in any single home cook's process — it is the natural consequence of working without laboratory homogenization. For customers who want a known quantity without doing the math themselves, lab-tested options solve the variability problem by design.

Frequently Asked Questions

What is the basic formula for calculating THC in homemade edibles? Multiply the THC percentage of your starting material (as a decimal) by the weight in milligrams, then adjust for decarboxylation and infusion efficiency. Total THC mg = grams of flower × THC % (decimal) × 1,000 × 0.877 × infusion efficiency. For 7 grams of flower at 20% THC with 70% infusion efficiency, that works out to roughly 860 mg of activated THC across the whole batch.

How much THC is in one gram of cannabis flower? One gram of flower testing at 20% THC contains roughly 200 mg of potential THC. After applying the 0.877 decarboxylation factor, that drops to about 175 mg of activated THC before accounting for any loss during cooking.

Why does the 0.877 conversion factor matter? Raw cannabis flower contains mostly THCA, not active THC. Heating converts THCA to THC, and the molecules have different molecular weights — 0.877 reflects that molar-mass ratio. Skipping this step overestimates potency by about 12–15%, which is enough to push a moderate dose into an uncomfortably strong one.

How do you dose a batch correctly when serving sizes vary? Calculate the total THC in the entire batch first, then divide by the number of portions you actually cut. Weighing each piece on a kitchen scale after baking gives a much more reliable dose than estimating by eye, which can vary by 30–50% between pieces from the same pan.

How long does it take for a homemade edible to kick in? Most people feel effects within 30 to 90 minutes, with peak blood levels around 1.5 to 3 hours after eating. Wait at least two full hours before taking another dose, because homemade potency can vary piece to piece and a second dose on top of an in-progress first is the most common overconsumption pattern.

What is a standard serving of THC in an edible? New York State and most other legal states cap a single adult-use serving at 10 mg of THC. Beginners often start at 2.5 to 5 mg, while experienced users may prefer 10 to 15 mg per dose. A package cannot legally exceed 100 mg total in New York.

What temperature and time should I use for decarboxylation? Most home decarb recipes use 220 to 240 degrees Fahrenheit for 30 to 60 minutes. Lower temperatures preserve terpenes but extend the time; higher temperatures risk burning off THC. An oven thermometer is worth using because most home ovens run hot or cold by 20 degrees or more.

Cannabis is for adults 21 and older. Keep all cannabis products out of reach of children and pets. This content is intended for educational purposes only and is not a substitute for professional medical advice. Treehouse Cannabis serves adult-use customers in Rockland, Orange, and Westchester Counties in accordance with New York State regulations. Please consume responsibly and do not drive or operate machinery after consuming THC products.

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Treehouse Cannabis is a licensed adult-use dispensary serving Rockland, Orange, and Westchester Counties in New York. Customers can browse the current menu and place orders at treehousecannabis.com.