How it works
This tool answers the reverse question: not what to add, but what ratio is even reachable. The nic base occupies target mg/mL divided by base mg/mL of the batch, and flavour occupies its stated percentage; each drags in PG equal to its own PG content. Those two contributions added together give the minimum forced PG, and maximum achievable VG is simply 100% minus that. No batch volume is needed, because everything is expressed as a fraction.
Nic base PG is the lever with the largest effect. At the defaults, a 100 mg/mL base at 100% PG with a 3 mg/mL target and 10% flavour at 100% PG, 13% of the mix is locked as PG and your ceiling is 87% VG. Switch the base to 50% PG and forced PG drops to 11.5%. The Desired VG field changes nothing in the maths; it only drives the feasibility chip underneath the table.
The model is purely volumetric and takes your concentrates at their stated PG percentage, yet many flavourings are partly ethanol, water or triacetin, which behave like neither PG nor VG. It also assumes the nicotine base is entirely PG and VG apart from a negligible amount of nicotine itself. Nothing here accounts for steeping, mixing contraction, or the practical difficulty of pipetting the very small volumes that high-VG recipes demand.
Frequently asked questions
What is the highest VG I can reach with a 100 mg/mL PG base? +
At a 3 mg/mL target with 10% flavour, 87%. The base contributes 3% PG and the flavour another 10%. Drop flavour to 5% and the ceiling rises to 92%; raise the nicotine target and it falls again.
How do I make a genuine max-VG juice? +
Use a VG-based or 50/50 nicotine base, keep the target strength low, and pick concentrates that are not 100% PG. Set Nic base PG to 0 with 10% PG-based flavour and the ceiling becomes 90% VG rather than 87%.
Why does my juice come out thinner than the ratio I asked for? +
Forced PG from the base and flavour is easy to overlook. The PG contribution column shows exactly how many percentage points each source adds, so you can see where the unexpected extra PG in your finished bottle came from.
Does the Desired VG field change the result? +
No. Maximum achievable VG is derived from base strength, base PG, target nicotine and flavour alone. Your desired figure is only compared against that result, to report whether it is achievable and by what margin, or how far over the limit it sits.
Is high nicotine the reason I cannot hit a high VG ratio? +
Partly. The nic base occupies target divided by base strength of the batch, so 12 mg/mL drawn from a 100 mg/mL PG base takes 12% of the volume as PG on its own. At 3 mg/mL it takes only 3%.
Two liquids that behave differently
PG is thin, carries flavour well and produces more throat hit; VG is thick, sweet and produces more visible vapour. The ratio is a genuine hardware decision rather than a preference, because viscosity determines whether a coil can wick fast enough.
High-VG liquid in a tight coil with small wicking ports starves the wick and produces a dry hit — unpleasant and, on repeated occurrence, damaging to the coil. Higher-VG blends need larger wicking channels, which is why sub-ohm hardware and high-VG liquid go together.
Flavour concentrates and steeping
Flavour concentrates are usually PG-based, so a recipe with 10% flavouring is already carrying PG that has to be counted in the ratio. Ignoring it makes a nominal 70/30 mix something else in practice.
PG is also the more common irritant of the two, and sensitivity to it is a real reason people move to higher-VG blends.
Freshly mixed liquid frequently tastes different after a period of resting, as flavour compounds distribute and some oxidise. The ratio does not change during that, but the perceived result does, which is worth knowing before adjusting a recipe that simply has not settled.
