If you want to see the Math, here you go.
I find it easier to figure the Nicotine First and then work on the PG:VG Ratios
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If you want to go from 36mg to 12mg, divided 12/36 = .3333 => 33.33%
So I need 33.33% 36mg and then add 66.66% of "Something".
Since we want to make 3ml total, 33.33% of it will be 36mg 50:50 or 1ml . And the other 2ml ( 66.66% x 3ml ) will be "Something". So we put 1ml of 36mg Nicotine Base in the Bottle.
Now let's look at the PG|VG Ratio. We want to end up with 70% PG and 30 % VG
So the Total amount of PG in 3ml is going to be 3ml x 70% = 2.1ml of PG
Right now, in the Bottle there is 1ml of 36mg @ 50% PG, so In the Bottle there is .5ml of PG.
So subtract the .5ml of PG we have already in the bottle from the 2.1ml of the Total PG and we get 1.6ml of PG to add.
If the Flavoring is PG Based, which most are, then that will account for some of the PG that we need to add. We want 20% Flavoring. For this Batch which is 3ml, 20% of 3ml is .6ml
OK. So after adding .6ml of PG Based Flavoring to the Bottle we have .5ml of PG from the 36mg Nicotine Base and .6ml from the Flavoring, which adds up to 1.1ml of PG so far.
We said that the total amount of PG would be 2.1ml (70% of 3ml) and we have 2.1ml of PG in the Bottle, so lets add 1ml More of Pure PG to get the total to 2.1ml of PG.
The bottle now has 1ml of 36mg 50:50 Nicotine Base, .6ml of Flavoring and 1ml of Pure PG for a Grand Total of 2.1ml of PG.
Now the VG...
We want to end up with 30% VG. And 30% of 3ml is .9ml
There should be .5ml of VG inside the Bottle since Half of the 1ml of 36mg was VG (50% of 1ml).
It sound like we need to add .4ml of Pure VG to get us up to .9ml of VG.
So now we have 1ml of 36mg Nicotine base, .6ml of Flavoring, 1ml of Pure PG and .4ml of Pure VG.
I think were Done. Almost...
Why Don't we double check things. (Man am I going to be ...... if this Doesn't Work!)
Do the ml add up? 1ml of 36mg + .6ml of Flavorings + 1ml of Pure PG + .4ml of Pure VG = 3ml --- Check
How about the mg? 36mg to 12mg would be 1ml part 36mg to 2ml Parts something. .6ml Flavoring + 1ml Pure PG + .4ml Pure VG = 2ml --- Check
How About the Ratios:
We Want 70% PG, 70 % of 3ml = 2.1ml. .5ml came from the 1ml of 35mg + .6ml came from the PG + 1ml Pure PG = 2.1ml of PG --- Check
We Want 30% VG, 30 % of 3ml = .9ml. .5ml came from the 1ml of 35mg + .4ml Pure VG= .9ml of VG --- Check
Add 2.1ml +.9ml = 3ml --- Double Check
I think we got it.
So the Recipe to make 3ml is:
1ml of 36mg 50:50 Nicotine Base (33.33%)
1ml of Pure PG (33.33%)
.4ml of Pure VG (13.33%)
.6ml of Flavoring (20%)
Calculators are Great but I think Everyone who does DIY should be able to do a Calculation like this Once if they Had to. It's a good way to Double check you putting the Right Numbers in the Right Boxes on a e-Liquid Calculator.
BTW - Here is something Cool to Think About.
Once you do All this God Awful Math, why Do it Again? You Now Know the Percentages to make ANY amount of 12mg 70:30 20% Flavored e-Liquid. Just Write the Percentages down from the Recipe and use them Next time.
