How to calculate CBD mg and %?

So, let's say I take 5 grams of Cherry Wine strain flower which supposedly has up to 25% CBD and I make a tincture with 1 liter alcohol, how can I calculate mg of CBD in it?

Or if I make oil with it, how can I calculate mg of CBD per bottle?

What I'm trying to say is, if you wanted to sell CBD or tincture, how can you calculate % and mg so that people can figure the concentration/quality?

I think you'd need to get the bud tested for compounds, and then workout the math. You can get a decent idea of extractable compounds when making shatter by weighing the raw material vs the finished material, but you would still have to separate the lipids, THC and CBD to know for sure.

If you can confirm the CBD levels, edible math is still tough. Good luck.