DIY E-Liquid Mixing: Why PG/VG Ratio and Nicotine Strength Fight Each Other

Ask a new DIY mixer to make 60 mL of e-liquid at 3 mg/mL nicotine in a 30/70 PG/VG ratio and most of them will reach for a calculator that only solves half the problem: how much nicotine base to add. That gets the strength right, but it quietly ignores something that trips up almost everyone the first time — the nicotine base and flavour concentrate are themselves mostly PG, and every millilitre of them you add is also a millilitre pushing your PG/VG ratio away from your target before you’ve poured a drop of plain PG or VG. Get the order of operations wrong and a “30/70” mix can easily come out 45/55 instead. The E-Liquid Nicotine Mixing Calculator exists specifically to solve both constraints together instead of one at a time.

The nicotine dilution math is the easy part

Nicotine base comes concentrated — typically 100 mg/mL for freebase or 200 mg/mL for nic salts — and needs diluting down to whatever strength you actually vape, commonly 0–3 mg/mL for sub-ohm freebase or 25–50 mg/mL for pod-style salt nic. The formula is standard dilution math:

Nic base volume = (target strength × total batch volume) ÷ base strength

Mixing 60 mL at a 3 mg/mL target from a 100 mg/mL base needs (3 × 60) ÷ 100 = 1.8 mL of nicotine base. That part rarely surprises anyone — it’s the same C1V1 = C2V2 dilution logic used everywhere from bleach dilution to lab reagents. The part that trips people up is what’s in that 1.8 mL beyond nicotine.

Your nic base and flavour are already PG or VG

Nicotine base isn’t pure nicotine — it’s nicotine dissolved in a carrier, and that carrier is almost always PG, sometimes a PG/VG blend. Likewise, the overwhelming majority of commercial flavour concentrates are suspended in 100% PG. So the moment you add 1.8 mL of a 100%-PG nic base and, say, 6 mL of flavour concentrate (10% of a 60 mL batch) at 100% PG, you’ve already added 7.8 mL of pure PG to the mix — before adding a single drop of plain PG or VG. If your target ratio is 30% PG by volume, that’s 18 mL of the 60 mL total, and you’ve already committed 7.8 mL of it just from ingredients you needed for other reasons entirely.

The remaining PG to add is target PG minus PG-already-present, and the remaining VG works the same way: target VG minus VG-already-present. Whatever volume is left after nicotine and flavour is what actually gets split between added PG and added VG to land the mix on its target ratio — not the naive “just fill the rest with VG” approach that ignores the PG already baked into your other ingredients.

When the target ratio isn’t reachable

Here’s the constraint that a lot of homemade spreadsheets miss entirely: sometimes your nic base and flavour supply more PG than your target ratio allows for, and there’s no way to subtract PG once it’s already dissolved into the base and flavour concentrate. If you’re mixing at a low total volume, a high flavour percentage, and a low-PG target (say, 20/80 for maximum vapour production), the PG contributed by a 100%-PG nic base and 100%-PG flavour concentrate alone can exceed 20% of the total before you’ve added anything else. In that case, the honest answer isn’t “add negative PG” — it’s that the target ratio is unreachable with those ingredients at that flavour percentage, and the achievable ratio needs reporting instead. A calculator that silently produces a negative number, or clamps it to zero without telling you, is quietly handing back a mix that isn’t actually the ratio you asked for. This is why the achievable-ratio warning matters more than the headline recipe numbers — it tells you when to reach for a VG-based nic shot or dial back the flavour percentage instead of trusting a number that can’t be true.

Nic salts change the density and the dosing curve

Salt nicotine typically ships at double the concentration of freebase (200 mg/mL vs 100 mg/mL) specifically because it’s absorbed differently and formulated for pod systems that vape at much lower wattage and produce far less vapour per puff — so hitting the same nicotine intake needs a higher mg/mL to compensate for lower vapour volume. Mixing math is identical either way (it’s still C1V1 = C2V2), but plugging in the wrong base strength for the nic type you actually have is one of the most common real-world mixing mistakes, since 100 mg/mL and 200 mg/mL bottles often look nearly identical on the shelf.

Converting to grams matters too

PG and VG have different densities — PG is about 1.036 g/mL, VG about 1.261 g/mL, and nicotine base sits close to 1.01 g/mL — so a recipe measured by volume doesn’t translate directly to weight on a scale, and a lot of mixers weigh ingredients for precision rather than relying on syringe markings. Converting every ingredient’s volume to grams using its own density, rather than one blanket density for the whole batch, is what keeps a scale-based mix matching a volume-based one.

Where to run the numbers

Enter your target batch size, nicotine strength, nic base type and strength, target PG/VG ratio, and flavour percentage into the E-Liquid Nicotine Mixing Calculator to get the exact mL and gram amounts of nic base, flavour, PG and VG — with a clear warning if your target ratio isn’t actually achievable with those inputs, instead of a recipe that quietly misses it.

This article and the linked calculator are general information about the arithmetic of e-liquid mixing, not safety or medical advice. Concentrated nicotine is toxic in small volumes if absorbed through skin or ingested — always handle nic base with gloves, keep it in child-resistant containers, and follow the safety guidance from your nicotine supplier.