The Cannabis Encyclopedia.

How to read this THC and CBD calculator

This potency calculator turns three numbers you already have, the weight of your flower, its THC or CBD percentage, and the volume of carrier oil, into a single figure that matters: milligrams of cannabinoid per millilitre, and per dose. Enter your inputs above and it does the arithmetic that most dosing mistakes come from getting wrong by hand.

What formula does the THC oil calculator use?

The core sum is: flower weight in grams, times THC percentage, times 10, gives total milligrams of THCA. Decarboxylation converts that to THC at a maximum of 87.7 percent by mass, because the carboxyl group leaves as carbon dioxide. A real home extraction then transfers only part of it into the oil, commonly 40 to 90 percent depending on the carrier. The full arithmetic is here, and the extraction efficiency page covers the transfer step.

Why does the calculator not just multiply by 100 percent?

Because two losses are unavoidable and pretending otherwise is the single biggest cause of edibles that are weaker than expected. Decarb caps conversion at 87.7 percent, and no home method transfers all of that into fat. A calculator that assumes a clean one-to-one gives a number two to three times too high. This one applies both factors so the dose you plan for is closer to the dose you get.

What flower to oil ratio should I use?

There is no single right ratio; it depends on how strong you want the result. A common starting point is roughly 7 to 14 grams of flower per 240 to 480 millilitres of oil. Enter your own figures above to see the milligrams per dose that ratio produces, then adjust. For which oil to use, see the carrier oil comparison.

How do I turn the result into a safe dose?

Once the calculator gives you milligrams per millilitre, a first dose for someone new to edibles is 2.5 to 5 milligrams of THC, waited out for a full two hours before any more. The complete edible dosage guide sets out the bands by tolerance. If a batch you calculated carefully still felt weak, why edibles do not work walks through the causes in order, most of which sit in the decarb step rather than the maths.

Does the calculator work for tinctures and CBD?

Yes. The same relationship holds for a CBD percentage or a THC-to-CBD ratio, and for an alcohol tincture rather than an oil, because the calculator works from cannabinoid content and volume rather than from the specific carrier. Enter the percentage on your product or lab result and read the per-millilitre figure.