TUTORIAL 3  Calculating Flavour Percenage Volumes
PreNote: I recommend the use of protective equipment such as latex gloves when undertaking mixing of eliquids. Furthermore, I recommend the use of a clean and dedicated mixing area to prevent cross contaminations, with adequate spill control and clean up equipment.
This thread is NOT intended as a full “How to DIY” tutorial, but rather, is intended solely to show how percentages in eliquid recipes can be directly translated to volumetric additions to an eliquid mix.
In short – this method is to mix flavouring concentrates BY VOLUME. This tutorial compliments my write up on calculating the correct addition of nic base to a solution, which can be found in Tutorial 2.
So… How do I translate the 7%, 3%, 2%, 0.5% part of a recipe into volume?
It is a simple matter of working out percentages.
When mixing you will know all of the variables you need to calculate the percentages of any given recipe into volumes to add into your mix.
You already know:

The total end volume you want to achieve (in millilitres).

The percentages of each flavour concentration.
What you don’t know is the volumes required to make the mix satisfactorily, however, you have all of the required information to calculate this.
These are simple two step equations to translate the percentage of a concentrate to a volume (in millilitres).
First, we need to find 1% of our end required volume. This is the easiest method, as everything else can be taken from this 1% once known.
To make it simple in the first instance, let’s use a standard 30mL bottle (ie; aiming for a finished result of 30mL of eliquid).
So, to find 1% of 30mL, we simply divide it by 100 (as we know there is 100% in the total):
Now, we know that 1% of our 30mL is 0.3mL. Simple, yes!
From here, we simply multiply out the calculated 1% by whatever factor we need to.
For example, let’s take my recipe for Sparkling Raspberry Limeaide:
(FA) Lime Tahiti Cold Pressed – 2%
(FA) Lemon Sicily – 2%
(TFA) Champagne – 2%
(INW) Raspberry Konkentrat – 1%
So, we can work out the required volumes by multiplying out our known 1% (which is 0.3mL) by the factors given by the required percentages as follows:
So we know we need to add:

0.6mL of Lime;

0.6mL of Lemon;

0.6mL of Champagne; and,

0.3mL of Raspberry.
….completing the flavour portion of this mix. This will also give us a flavour volume of:
(3 * 0.6mL) + 0.3mL = 2.1mL
which equals
(3 * 2%) + 1% = 7% by volume.
Now.......
Lets try it with a more complex recipe, in a different volume – take my recipe for Ichigo Keki:
(TFA) Strawberry Ripe  4%
(CAP Sweet Strawberry  2%
(FA) Red Touch  2%
(FW) Cake (Yellow)  4%
(FW) Sweet Cream  3%
(TFA) Bavarian Cream (DX)  1.5%
(TFA) Dulce De Leche  1%
And lets assume I want to make a 65mL bottle this time.
Step 1:
Calculate one percent of the total:
Now, work out the required volumes of each requisite ingredient as follows:
So we know we need to add:

2.6mL of TFA Strawberry;

1.3mL of CAP Strawberry;

1.3mL of Red Touch;

2.6mL of Yellow Cake;

1.95mL of Sweet Cream;

0.975mL of Bavarian Cream DX; and,

0.65mL of Dulce De Leche.
…completing the flavour portion of this mix. This will also give us a flavour volume of:
(2 * 2.6mL) + (2 * 1.3mL) + 1.95mL + 0.975mL + 0.65mL = 11.375mL
which equals
(2 * 2%) + (2 * 4%) + 3% + 1.5% + 1% = 17.5% by volume.
Using this method, you can calculate any required concentrate volumes for addition to a mix, for any required end amount of eliquid desired, using any recipe.
It doesn’t matter if your recipe has one, or one hundred ingredients.
You will also notice that I have made a point of jotting down the following:
1) The end total percentage of flavour concentrates in my mix.
2) The end total volume of flavour concentrates in my mix.
This is important if you are going to calculate your end PG/VG ratio  or, look at what additional PG and VG you need to add to get to a specific ratio.
I will however not touch on that in this particular post, as it is a thread and tutorial on its own.
Happy Mixing!!!!!!