With some simple marijuana math you can estimate the total Milligrams of THC in your own homemade edibles.
First, identify the percentage of THC in the strain you’re cooking with. On average, most medical strains have about 15-25 percent THC. If your cannabis is not from a dispensary and you do not have lab tests for the strain, estimate at 10 percent THC.
You are starting out with a quarter ounce of marijuana, that’s 7 grams. An eighth would be 3.5 grams.
Every 1 gram of cannabis bud has 1,000mg of dry weight. If a strain has about 10% THC, ten percent of 1,000mg would be 100mg (1000 divided by 10=100). So for cooking or baking at home, it is safe to assume that a gram of cannabis contains at least 100mg THC.
Using this dosing measurement formula, you do can the math accordingly to find out how much THC per serving. Take the amount of ground marijuana, convert it to milligrams and divide it by the recipe yield to determine a per-serving dose of THC. A starting dosage for beginners is 5-10 milligrams per serving. Three grams of ground marijuana equals 300mg THC. 300mg divided by the recipe yield. So if you were to make a box brownie mix (my preference is Ghirardelli) and you used 3 grams of 10% cannabis in the oil and made 16 brownies each brownie would have about 18.75 MG of THC (300 divided by 16 = 18.75).