Shortfill vs nic salt vs freebase: the complete e-liquid guide

Nearly every bottle on our shelves is one of three things: freebase e-liquid, nicotine salt e-liquid, or a shortfill. They are not interchangeable: each suits a different device and a different draw. Here is what separates them, the law that shapes them, and how the 2026 duty changes the sums.

The three types at a glance

Freebase and nicotine salt are both ready-to-vape e-liquids that already contain nicotine. The difference is the form the nicotine takes, which changes how the vape feels. Shortfills are a third category: a larger bottle of nicotine-free liquid that you top up with nicotine yourself. All three are governed by the same UK product law, the Tobacco and Related Products Regulations 2016, which we reference throughout.

Freebase e-liquid

Freebase is the original, traditional form of nicotine e-liquid. At higher strengths it produces a pronounced "throat hit", the catch at the back of the throat that many long-term smokers are used to. That firmness is the reason freebase at 12mg/ml and above tends to feel harsh in low-powered pods, which is where nicotine salts come in.

Freebase is most at home in mouth-to-lung tanks and lower strengths, and in higher-VG blends for direct-to-lung devices at 3mg/ml and 6mg/ml. UK law caps the nicotine strength of any nicotine-containing e-liquid at 20mg/ml, and a nicotine refill bottle at 10ml.

Nicotine salt e-liquid

Nicotine salts are made by adding an acid (commonly benzoic acid) to freebase nicotine. The result is a smoother inhale at higher strengths, so a 20mg/ml salt feels far gentler than a 20mg/ml freebase would. Salts also tend to satisfy a nicotine craving more quickly, which is why they became the standard for pod systems and the disposables that preceded today's refillable kits.

You will usually see salts at 10mg/ml and 20mg/ml. They pair best with low-power, higher-resistance mouth-to-lung devices, pod kits and MTL tanks, rather than high-wattage sub-ohm hardware. The same legal limits apply: 20mg/ml maximum strength, 10ml maximum bottle.

Shortfills, and how they legally work

A shortfill is a larger bottle, typically 50ml or 100ml, of nicotine-free (0mg) e-liquid. Because it contains no nicotine, it is not bound by the 10ml refill-container limit, so it can be sold in a bigger bottle. The bottle is deliberately "short-filled": a 60ml bottle might hold only 50ml of liquid, leaving headroom.

Into that headroom you add a nic shot: a 10ml bottle of unflavoured nicotine e-liquid, usually 18mg/ml or 20mg/ml, which is itself a fully compliant 10ml/20mg product. Adding one 10ml nic shot at 18mg/ml to a 50ml shortfill brings the whole 60ml up to roughly 3mg/ml. That is the standard way UK vapers buy larger volumes of a favourite flavour while staying inside the law.

Two limits still apply regardless of bottle size: your tank or pod holds a maximum of 2ml, and the finished liquid must not exceed 20mg/ml.

VG and PG, explained

Every e-liquid is built on two carrier liquids, blended in a ratio you will see on the label, for example "70/30".

• VG (vegetable glycerine) is thicker and produces more vapour. Higher-VG blends (such as 70/30) suit sub-ohm, direct-to-lung devices.
• PG (propylene glycol) is thinner, carries flavour and nicotine more sharply, and gives a firmer throat hit. Higher-PG or balanced blends (such as 50/50) suit mouth-to-lung pods and MTL tanks.

As a rule of thumb: 50/50 for pods and MTL, 70/30 (high-VG) for sub-ohm clouds. Most shortfills are high-VG; most nic salts are 50/50.

What the 2026 vape duty does to each format

From 1 October 2026, Vaping Products Duty adds £2.20 per 10ml to all vaping liquid, regardless of nicotine content, so nicotine-free shortfills are taxed at the same rate as nic salts and freebase. Because VAT is charged on the duty-inclusive price, the real increase on the shelf is roughly £2.64 per 10ml once VAT is added on top.

The duty is charged by volume, so larger shortfills carry proportionally more of it. Here is the duty added to common formats:

A 50ml shortfill plus two nic shots, for instance, carries duty on the full 70ml of liquid. The figures above are the duty component only; they are added to the pre-duty price of the product. For the full picture (key dates, the duty-stamp scheme, how to plan sensibly) see our 2026 vape tax guide.

Which should you choose?

• Pod kit or MTL device, want a smooth higher-strength hit: nicotine salts at 10mg/ml or 20mg/ml.
• MTL tank, prefer a firmer throat hit at lower strength: freebase at 6mg/ml or 12mg/ml.
• Sub-ohm, direct-to-lung, chasing flavour and vapour: a high-VG shortfill at 0mg or 3mg/ml.
• Want a large volume of one flavour: a shortfill plus nic shots to your preferred strength.

Not sure which strength matches your habit? Our nicotine strength guide has a clear reference table, and the difference between draw styles is covered in MTL vs DTL.

This guide gives factual information about the products we sell and the rules that govern them. It is not medical or stop-smoking advice. If you have questions about your health or about quitting smoking, the NHS Better Health service is the right place to start.