500mg of THC requires 500mg / 920mg/g = 0.543g
500mg of CBD requires 500mg / 840mg/g = 0.595g
0.543 + 0.595 = 1.138g
If you only want 1g, that ratio needs adjusted.
Multiply each by 1/1.138 = 0.879
0.543g x 0.879 = 0.477g thc distillate per cart
0.595g x 0.879 = 0.534g CBD distillate per cart
How big are the carts. If they are 1 gram carts, it’s impossible to fill them with 500mg of each cannabinoid.
I have my formulations setup as formulas in xcel so I can just plug in variables such as batch size or distillate potency. It’s an algebra equation if you want to create a repeatable formulation with distillates of varying potency.
@Listen_Up_Sonny that’s exactly what I’m after… a repeatable formula tunable based on distillate potency, ratio of of mixture 1:1,2:1, and terpenes
You really don’t want someone else to solve this for you.
Get the math right once then teach excel is an awesome strategy
Rely on someone else to teach excel?
Bad for your brain…and cannabis is already doing a number on your mental capacity, so fight that at every step.
Thanks @cyclopath all I’m after is the math… even different variations of what others are doing… excel is simple but of course why re-invent the wheel
Don’t mind me. I confuse teaching folks to fish with smacking them upside the head with fish. I’ll get it eventually 
I feel like an episode of NCIS getting smacked in the back of the head haha… I get it though lots of folks are just lazy and want others to do everything for them…
The dimensional analysis is simplified by the fact that THC and CBD are isomers and so have the same molecular mass… so 1 gram THC = 1 gram CBD. If your distillates were of equal strength in the target cannabinoid you could weigh gram for gram of distillate and be done. No such luck.
Multiplying the grams of distillate by percent cannabinoid will give you the actual mass of cannabinoid in the distillate.
As mentioned elsewhere in the thread since both your distillates are less than 100% (because… duh they’re not isolates) you won’t get 500 mgs of each in a 1 gram cart.
I’d start by calculating how many mgs of cannabinoid are in 0.5 grams of the least concentrated distillate, then calculating how much of the other you need to get to a 1:1 mix. From there you can see how much room you have. But that’s if you’re just trying to fill a single cart.
Otherwise just figure out 1:1 for your bulk mix and fill carts as usual.
You may have a problem with the cbd crystalizing over time if you go much over ~42%. Its happened to me in the past when I formulated the cart at 50% cbd and 35% thc by weight and about 6% terpenes. You may have better luck with distillate though I was using isolate.
Great resource, lousy URL (still full of googly-bits)
Here it is properly trimmed…
https://toptipbio.com/c1v1-equation/
Edit: just because these two need cross-linked
Dilution calculator for extract-isolate combinations
This is perfect!!! Now m going to have to start a new topic on what in the world to use to dilute it with haha
This is genius!! Exactly the thing I was looking for
Terps and only terps. Nothing else is safe to dilute with other than other noids.
Terps will only dilute so much right? Especially based on the formula from above…
Thanks @cyclopath , I was lazy. It’s a great little formula I wish someone would have taught me sooner
Even I know how to do math once you figure out your formula you want to send it into the lab and have it tested to see if you were accurate in the first place
Have you thought about using CBC and or CBT? I find at percentages of either/both between 5-10% to be good for vapes
No, I haven’t…. What’s the cost and where do you obtain such an item