Cannabutter Calculator: How Strong Are Your Edibles?

Every cannabutter calculator — ours included — runs the same simple equation. The only honest part is being clear about the one fuzzy variable in it:

total mg THC = grams of flower × (THC% ÷ 100) × 1000 × infusion efficiency
dose per serving = total mg ÷ number of servings

The first three numbers are knowable: weigh your flower, read the THC % off the label or COA, and 1,000 just converts grams to milligrams. The fourth — infusion efficiency— is the one nobody can measure exactly at home, because it depends on how well you decarbed, your fat, your cook, and your strain. That's why the calculator lets you set it, and why your result is a sensible ceiling, not a guarantee. Worked example: 7 grams of 20% flower at 70% efficiency is 7 × 0.20 × 1000 × 0.70 ≈ 980 mg in the batch, or about 41 mg per servingacross 24 gummies — a strong dose, so you'd likely make smaller ones.

Raw cannabis barely gets you high if you eat it, because the plant makes THCA — an acidic, non-intoxicating precursor — not THC. Heat converts THCA into active THC by knocking off a carboxyl group, a reaction called decarboxylation. Smoking does it instantly with the flame; for edibles you have to do it on purpose in the oven first. Skip or rush it and your butter will be weak no matter how long you simmer.

The research-backed target is a thin layer of ground flower at about 240°F (115°C) for 30–45 minutes. A controlled bake in that range converts nearly all the THCA while preserving the resulting THC and much of the terpene profile; pushing the heat far higher, or relying on an uncontrolled stovetop, can destroy a meaningful chunk of the THC instead of activating it (decarboxylation kinetics study, 2016). Here's the working chart:

THC is fat-soluble, not water-soluble, which is the whole reason cannabutter and cannaoil work: the activated THC dissolves into the fat. You gently simmer your decarbed flower in butter or oil — ideally low, around 160–200°F, for 2–3 hours, never a rolling boil, which scorches cannabinoids. More fat and more contact time pull more THC across; that's why full-fat butter or a high-fat oil like coconut outperforms a watery infusion.

But it never all transfers. Real-world home infusions move roughly 60–90% of the available THC into the fat, with about 70% a realistic default — the number our calculator starts on. The rest stays bound up in the spent plant material you strain off. This is exactly why an honest calculator asks for efficiency instead of pretending every milligram makes it in: assume the higher end, and you'll rarely make something stronger than you planned.

When you strain, pour through cheesecloth or a nut-milk bag and let gravity do the work. Wringing the bag hard squeezes bitter chlorophyll and plant matter into your butter — a little more yield, a lot more grassy taste.

Now you use the per-serving number. The trap with homemade edibles is that the dose hides in the volume — a tablespoon of strong butter baked into one cookie out of a dozen is wildly different from the same butter spread across all twelve. Mix your infused fat thoroughly into the recipe so the THC is even, and portion deliberately.

Then dose like edibles deserve: a 10 mg serving is the common "standard" dose, 2.5–5 mg is a gentle starting point, and edibles take 30 minutes to 2 hours to land — so wait the full two hours before taking more. Our edible dosing calculator turns the per-serving milligrams into a starting dose for your tolerance, and if a batch ever gets away from someone, our guide to coming down from being too high covers what actually helps. For how long the effects last once they hit, see how long a weed high lasts.

You can't be lab-precise at home — and that's fine

Be skeptical of any tool promising an exact milligram from a kitchen. Your flower's labeled THC % is already an approximation, and efficiency shifts batch to batch. An at-home potency tester gets you closer if you make edibles regularly, but the durable habit is to estimate conservatively, start low, and go slow. Underestimating your dose costs you a slightly weaker cookie; overestimating costs you a miserable few hours.

Storage and shelf life

Cannabutter keeps about 2–3 weeks in the fridge and up to 6 months frozen, in an airtight, opaque container away from light and heat (both degrade THC over time). Label it clearly with the date and your estimated dose per serving — the single best habit for not surprising a roommate, a guest, or future you.