How to Calculate the Potency of Edibles

Rambo December 28, 2015 8
How to Calculate the Potency of Edibles

I’ve never liked eating edibles and it’s not because of the taste. The reason I don’t like edibles is because I have no clue how potent they will be.

When I smoke a joint I may not know the percentage of THC the cannabis contains or how much of the joint I will need to smoke. It doesn’t matter, I can take a toke or two and see how I feel. By the time it’s been passed around I have a pretty good idea of how strong it is. I can take another toke, or not, it’s my call. I know what I am signing up for.

Edible don’t work this way. No one can tell how potent edibles are by the size or the taste. The consumer really has nothing to go on. To make matters worse, edibles must be processed by your body before you feel the effects and this can take an hour or more. You won’t know for quite some time if you’ve had too little, too much or just enough.

Don’t expect to read it on the label. I’ve seen plenty of edibles for sale at reputable dispensaries with labels that don’t even try to list the potency. Those that make an attempt often do so in an unintelligible way. How about the single brownie advertised as 12 doses? Am I really only supposed to eat a few crumbs of the brownie? But, it looks soooo good! I want to eat like 3 of them. I’ve seen other labels that state 1.5 grams Sativa. Really? What does this tell the consumer? This tells you only slightly more than nothing at all.

What’s sad is that calculating the potency of edibles is actually pretty easy. Here is a simple formula for doing just that.

How to Calculate Potency

These days it’s pretty easy to find out the potency of the cannabis you purchase. Most dispensaries have their bud lab tested and they advertise the percentage of THC it contains. Assuming the dispensary is honest, you’ve got a good place to start. If you grew you own or purchased a decent amount there are labs popping up all over that can test potency for around $100.

Say you purchase 3.5 grams (approximately 1/8th ounce) of decent outdoor bud that is advertised as 15% THC. This does not mean you have 3.5 grams of THC, it means that 15% of your 3.5 grams is THC. Lets do some math.

Potency Formula

First let’s convert grams to milligrams.

3.5 g of cannabis x 1000 = 3500 mg of cannabis

We know that only 15% of the 3500 mg is actually THC.

15% of 3500 is the same as .15 x 3500 = 525 mg of pure THC

If we use this 3.5 grams of outdoor cannabis to make butter (or oil) and assuming we are able to extract 100% of the THC into the butter, we know the butter will contain 525 mg of THC.

If we use all of this butter to make a batch of 12 brownies, we know that each brownie will have about 43.75 mg of THC.

525 mg of THC divided by 12 brownies. = 43.75 mg THC per brownie

So How Much is a Dose?

If there is 43.75 mg of THC in a brownie, does that mean 1 brownie is a dose? This all depends on the person eating the brownie. There may be 200 mg of Ibuprofen in an Advil but that doesn’t mean 1 advil is a dose. In fact the bottle directs adults 12 and older to take 1-2 capsules. THC is the same way. You have to figure out what works for you. Luckily, unlike some medications, it’s much more difficult to cause permanent damage if you take a little too much THC.

We don’t all have the same comfort level with the psychoactive effects of cannabis and our bodies don’t all metabolize cannabinoids in the same way. For some, 20 mg of THC may be the perfect dose. For those with a higher tolerance or greater comfort level with the effects, 100 mg or more may be more appropriate.

The proper dose is something the user must discover for themselves. This may take a bit of trial and error. Start small and gradually work your way up to higher doses. Once you know how many mg of THC in right for you, use this formula to calculate the correct potency for making your edibles. If you keep your recipes consistent, you’ll have great tasting edibles with very predictable potency.

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  1. inkbuddy December 29, 2015 at 2:43 pm -

    I read on this same website that THCA turns into THC when heated, whether in the oil or from smoking it. Is this taken into account
    or do we have to have the oil tested instead of the weed? Seems like a HUGE expense for NOTHING! I’d rather spend that $100 on more weed.
    I prefer to treat it like any other drug. Start small, give it some time (50 minutes for me), if you feel like you want, fine. If you need more gauge how much by how the last bit affected you. The rest of your baked goods will contain approx. the same dose.
    NEVER take two hits of Orange Sunshine just because the acid head that sold it to you says “Take two, this batch is weak.”
    I get off on ½ of 1 of my brownies and my girlfriend can barely eat a small corner. Know your limits.

  2. Paul January 26, 2016 at 8:39 pm -

    Well thought out post. Thank you. I’m a psychologist in NJ who’s extremely frustrated about the lack of research into cannabinoids. Do we really have to wait another 20 years for research independent of big pharma tells us what works for what? In the meantime, thanks again for your post.

  3. marie April 7, 2016 at 8:39 am -

    This was great ?

  4. domain April 8, 2016 at 5:09 am -

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  5. Mike April 10, 2016 at 6:25 am -

    You say “assuming we can extract 100% of the THC into the butter”. I have always felt that some of the THC etc… will remain in the bud from which the butted was separated, and therefore may also have some benefit, It can be blended into a smoothie etc…, rather than simply tossing it out. Thanks for your article.

  6. CL Sumruld May 9, 2016 at 3:29 pm -

    Having recently beat prostrate cancer with refined oil and knowing others with far worse stages than mine who have killed cancer cells with cannabis. Why is it still against the law. My urologist put it simply “the government givith and the government takeath away.

  7. Michael M Dedek May 24, 2016 at 9:55 am -

    I’ve got a quick, easy, economical & reliable way to make brownies based on this formula. You can probably find ways to optimize it, but I did a fair amount of research and several months of regular use has proven this easy, reliable, and effective. I use it medicinally, 3-4 times per day (I smoke occasionally for recreational use), for pain and bipolar disorder (it has allowed me to eliminate 3 of the 5 psych meds I was on, and reduce the dosage of other two – also got off a really bad prescription pain pill addiction). It basically takes 2 cups of coconut oil, 1/4 oz of kind bud, 4 boxes of brownie mix, and some eggs & water.

    First, I decarb the bud. Depending on looks, and based on comparisons with bud sold in Seattle dispensaries, I find 15-20% is a fairly accurate THC estimate (well, THC-A at that point). The best bud I saw at the dispensaries ranged 21-26%. If it’s really sticky and sparkly, it might be > 20; if it’s on the puny side it might be < 15. Assuming 15%, 7g x 15% = 1050mg THC-A. 20% would be 1400mg.

    I use refined flavorless coconut oil, because it's totally saturated fats (but not trans-fats – it's actually healthy). I double-boil 2 cups of oil with 1/4oz decarb'd bud for 3 hours, stirring every 15 minutes or so. Strain with cheesecloth and cool; pour back in the original bottlle, Using bud requires little enough vegetable matter that no taste is imparted to the oil. You could use this oil for anything; dose carefully (remember there are 100 doses in that bottle!).

    2 cups makes 4 boxes of standard brownie mix. (or use 1/2 in your fave recipe). Recall we estimated 1000mg+ THC, which is 100 10mg doses. I've been smoking for over 30 years, and have had huge tolerances at times, but try to keep it mellow now – 10-20mg (1-2 brownies) is usually enough for me. My wife is mj-naive and takes 10mg max (1/2-1).

    So anyway, why did I mention 4 boxes? Because 1000mg+ THC = 4x250mg+ THC, so each batch of brownies has 250mg+ THC = good for 20-24 doses of 10mg+.

    Standard dose for edibles in Washington is 5mg, but that's considered a tad on the low side. Like I stated, 10-20mg is enough for me, usually 10 through the day and 20 at night, while 5-10 is good for my wife (who uses it perhaps once/day for pain & migraines). But that brings me to the point of why I repeatedly used the "+" sign after the mg amounts – remember they are _estimates_ based on the appearance of the weed and some knowledge of weed. Regardless of your experience with marijuana, as with all edibles, START SMALL and increase. This recipe seems to make pretty potent brownies, but there are so many variables that it's best to start with 1/2 brownie (1/40th of a batch). You can always eat more!

    So for under $100 (cost of 1/4 in the midwest USA, plus the cooking supplies), I get about 80 brownies. Reliable and consistent enough to use medicinally.

  8. Bobzilla September 9, 2016 at 3:45 pm -

    I vape with a Magic Flight Launch Box so I save up my ABV(already been vaped) bud till I have about 20 grams.I then get a Betty Crocker Brownie mix that calls for butter. I simmer the ABV in coconut oil for 2-3 hrs in a small crock pot on low..Use the amount called for in butter on the mix and replace it with The ABV coconut oil extract.Bake at a lower than called for baking temp, I use 275 degrees, for about 50% more or longer than the box calls for. Its usually about 1 hr 20 minutes instead of , like 30, listed on the box. I usually check it with a toothpick at 45,60 and then 95 minutes./ Cook till pick comes out clean. Makes about 24 brownies that are 4 way for me. Very Good medicine!!!