Shortfill E-Liquids and Nic Shots Explained: How They Work in the UK

A shortfill e-liquid is a bottle, usually 50ml or 100ml, sold at 0mg nicotine and filled short of its full capacity to leave room for added nicotine. It's allowed to come in a bottle far bigger than 10ml because the UK's 10ml container limit under the Tobacco and Related Products Regulations 2016 only applies to nicotine-containing e-liquid, not liquid with none in it.

A nic shot is the other half of the equation: a separate 10ml bottle of concentrated nicotine, typically 18mg or 20mg per ml, that meets TRPR's own rules for nicotine-containing products in full. Pour one or more shots into a shortfill and shake it properly, and the finished mix has to land at or under the UK's 20mg/ml legal maximum, the same ceiling that applies to every nicotine e-liquid sold in this country. This guide covers how that split works, the maths behind working out your own mix, matching VG/PG ratio to your device, and when the format isn't the right first buy.

What Is a Shortfill E-Liquid?

A shortfill is exactly what the name says. It's a bottle of e-liquid that isn't filled to the top on purpose. Buy a "100ml shortfill" and you'll typically find 70ml, 80ml or 100ml of actual liquid sitting inside a bottle sized for more, depending on the brand and range. That gap is called headroom, and it exists so you can add nicotine before you vape it.

Every shortfill sold in the UK carries 0mg nicotine at the point of sale. That's the entire mechanism. Flavour and a VG/PG base, no nicotine, in bottle sizes that would be against the law for a nicotine-containing e-liquid. Doozy's Infinity 100ml Shortfill 70/30 and Infinity Pod Fill 100ml Shortfill 50/50 are a useful side-by-side example: same flavour range, two different VG/PG bases, both sold at zero nicotine until a shot goes in.

Shortfills exist because of a plain market gap. A vaper who already knows their flavour and roughly what strength suits them doesn't want to keep working through 10ml bottles one at a time. A shortfill format lets a brand sell far more liquid in one bottle at a lower price per ml, and it lets the customer set their own final nicotine strength rather than being stuck with whatever a pre-mixed 10ml bottle happens to offer.

Ranges like Seriously Pod Fill x2 100ml Shortfill and Seriously Tropical Shortfill 100ml 70/30 sit in this bracket too, and Vape Desires stocks both formats across the e-liquids collection and the dedicated Doozy 100ml e-liquids collection.

Why Are Shortfills Sold at 0mg Nicotine?

This is the part that trips people up, because a 100ml bottle looks like it should be illegal next to a 10ml nic salt bottle. It isn't, and the reason comes straight from the regulation.

The TRPR 10ml Rule and How Shortfill E-Liquid Sits Outside It

The Tobacco and Related Products Regulations 2016 (TRPR) is the UK law that governs e-cigarettes and e-liquid. Regulation 36 sets three limits that matter here: nicotine strength can't exceed 20mg per ml, a refillable tank can't hold more than 2ml, and nicotine-containing liquid sold for refilling has to come in a dedicated container of no more than 10ml. You can read the wording directly on legislation.gov.uk.

Read that last limit again: it applies to nicotine-containing liquid. A 100ml bottle of 0mg e-liquid has no nicotine in it, so the 10ml container rule has nothing to bite on. GOV.UK's own guidance confirms the restriction is aimed specifically at "nicotine-containing e-liquid," not flavoured liquid in general, which is why the size cap on refill containers doesn't touch shortfills at all (see GOV.UK: e-cigarettes, regulations for consumer products).

This also explains why shortfills don't need MHRA product notification. Notification under TRPR is a nicotine-containing product requirement: manufacturers submit ingredient and toxicology data to the MHRA before a nicotine e-liquid or device goes on sale, and the product then appears on the MHRA's public register. A 0mg shortfill isn't a nicotine-containing product, so it falls outside that regime under Regulation 36, and is covered instead by general consumer product safety law rather than the vape-specific TRPR nicotine rules. The nicotine shot you add afterwards is a different story, and it does need to clear that bar in its own right, which is the next section.

Worth being precise here: this is not a loophole in the sense of something skirting the spirit of the law. Shortfills are one of the more deliberate, well understood parts of UK vaping regulation, and every serious UK e-liquid brand builds its range around this exact split.

What Is a Nic Shot?

A nic shot is a small bottle, always 10ml in the UK, containing concentrated nicotine in a VG/PG base with no flavour of its own (or occasionally a very neutral one). It's sold on its own, separately from the shortfill, and it's the piece that actually brings nicotine into the finished mix.

Nic shots comply with TRPR as nicotine-containing products in their own right. They sit inside a 10ml container, as required, and the nicotine strength inside them can't exceed the same 20mg/ml ceiling that applies to any nicotine e-liquid sold in the UK. Most nic shots on the market, including Nic Nic's 10ml 18mg 100% VG shot, sit at 18mg or 20mg, right up against that legal cap, because a shot's whole job is to carry as much nicotine as possible into a small volume before it gets diluted.

Freebase Nic Shots vs Nicotine Salt Nic Shots

Not every nic shot is built the same way, and picking the wrong one for your shortfill is the most common mistake first-time mixers make.

A freebase nic shot is typically 100% VG. It's built to pair with high-VG shortfills, usually a 70/30 or 80/20 VG/PG split, aimed at sub-ohm tanks and direct-to-lung (DTL) devices. Freebase nicotine at higher strengths gives a more noticeable throat hit, which is part of why freebase mixes tend to stay at the lower end of the strength range, commonly 3mg to 6mg/ml once diluted, rather than being pushed toward the legal maximum.

A nicotine salt shot, like Nic Nic's Flavourless 50VG 10ml Nicotine Salt, is usually built at 50VG/50PG to match a 50/50 shortfill designed for pod kits and mouth-to-lung (MTL) vaping. Nicotine salts are chemically smoother at higher strengths than freebase nicotine, which is why salt-based e-liquids can sit at 10mg to 20mg/ml and still feel manageable on the throat. We've covered the underlying chemistry in more depth in Nic Salts vs Freebase Nicotine: Which Should You Be Using?, so this piece won't repeat that ground. The point that matters for shortfills specifically is matching: freebase shot into high-VG shortfill for DTL, salt shot into 50/50 shortfill for MTL. Mixing that up doesn't break any law, but it usually produces a mix that either scratches the throat far more than expected or feels weaker and less satisfying than the strength on the label suggests.

How to Work Out Your Shortfill and Nic Shot Mix

The maths behind a shortfill mix isn't complicated once you see it done once, and it's worth doing on paper rather than guessing, because getting it wrong either wastes nicotine or leaves you under-strength.

The formula is: total nicotine in mg (shot strength in mg/ml multiplied by shot volume in ml, multiplied by the number of shots) divided by the total finished volume in ml. That gives you the finished strength in mg/ml.

• Worked Example 1: One Nic Shot in a 90ml Shortfill
  Take a 90ml shortfill of 0mg e-liquid, sold with 10ml of headroom in a 100ml bottle, and add one 10ml shot at 18mg/ml. That's 18mg/ml times 10ml, which is 180mg of nicotine, added into a finished volume of 90ml plus 10ml, so 100ml. 180mg divided by 100ml works out at 1.8mg/ml, a light, all-day strength that suits a lot of pod kit users who want flavour and volume more than a strong hit.
  
  
• Worked Example 2: Two Nic Shots in a 70ml Shortfill
  Take a 70ml shortfill and add two 10ml shots at 18mg/ml. That's 20ml of shot liquid carrying 360mg of nicotine total (18mg/ml x 10ml x 2), combined with the 70ml base for a finished volume of 90ml. 360mg divided by 90ml comes out at 4mg/ml, a noticeably stronger mix than the single-shot example above, and a common choice for vapers who want something closer to a standard nic salt strength but in a much bigger bottle.
  
  
• Worked Example 3: One Nic Salt Shot in a 50ml Shortfill
  Take a 50ml 50/50 shortfill built for pod kits, and add one 10ml nic salt shot at 20mg/ml. That's 200mg of nicotine (20mg/ml x 10ml) into a finished bottle of 60ml. 200mg divided by 60ml gives 3.33mg/ml, roughly the strength of a mid-range nic salt bottle, just made in a 60ml batch instead of a 10ml one.

Why You Can't Push a Standard Shortfill Mix Anywhere Near 20mg/ml

Here's a detail that rarely gets explained: a shortfill and nic shot combination almost never gets close to the UK's 20mg/ml ceiling, and that's by design, not by accident. Even a fairly aggressive mix, two 20mg shots into a 40ml shortfill topped up to 60ml, only reaches 400mg divided by 60ml, which is 6.67mg/ml. To land at 20mg/ml from a shortfill base you'd need nearly the whole bottle to be nic shot, at which point you're no longer really buying a shortfill, you're buying nic shots with a token amount of flavour added.

That's the practical ceiling of the format. Shortfills are a low-to-mid-strength, high-volume system. If you want a genuinely high-strength e-liquid at or near 20mg/ml, the shortfill route isn't the right tool. A pre-mixed 10ml nic salt bottle from the nic salts collection does that job directly, without any dilution maths at all.

Matching Your Shortfill VG/PG Ratio to Your Device

VG/PG ratio decides how a shortfill behaves in your device, and it matters more than flavour choice for getting a satisfying vape.

High-VG shortfills, typically 70/30 or 80/20, are thicker and produce bigger, denser clouds. They're built for sub-ohm tanks and DTL devices with wide-bore drip tips and low-resistance coils that can pull that thicker liquid through efficiently. Push a 70/30 shortfill through a tight-draw pod designed for MTL and you'll likely get weak flavour, gurgling and a coil that struggles to wick properly.

50/50 shortfills, like the Doozy Infinity Pod Fill range, are thinner and designed specifically for pod kits and MTL setups, the same category of device that most people move onto after disposables. If your device takes prefilled 2ml pods and gives a tighter, cigarette-like draw, a 50/50 shortfill is almost always the correct base, paired with a nic salt shot rather than a freebase one.

Getting the VG/PG ratio wrong is a bigger practical problem than getting the strength slightly off. A 70/30 mix in the wrong device tends to leak, spit or burn out a coil early. A 50/50 mix in a sub-ohm tank tends to feel thin and underwhelming on flavour and cloud. Check your device's recommended VG/PG range before choosing a shortfill, not after.

Who a Shortfill and Nic Shot Setup Suits

Shortfills reward a specific kind of vaper, and they're not the easiest starting point for everyone.

They suit vapers who already know roughly what flavour they like and what nicotine strength works for them, because a shortfill is a bulk decision, not a trial size. They suit anyone who wants to set their own strength rather than pick from whatever fixed mg options a brand happens to bottle, since the shot count gives direct control over the final number. They suit vapers who get through liquid quickly and want a lower cost per ml, since a 100ml bottle plus shots almost always works out cheaper than the equivalent volume in 10ml nic salt bottles. And they suit people who are comfortable with a bit of DIY, pouring, shaking, checking a label, rather than wanting something ready to vape straight out of the box.

They're less suited to someone who just wants to open a bottle and go. If you can't yet say whether you prefer 50/50 or 70/30, or whether nicotine salts or freebase feel better on your throat, buying a shortfill first means guessing on two variables at once rather than one. There's no harm in trying it, but a pre-mixed 10ml bottle or a prefilled pod kit removes that guesswork while you work out your preferences.

Who Should Stick to Prefilled Pods or Ready-Mixed Nic Salts Instead of a Shortfill

Some vapers are better off skipping the shortfill route entirely, at least to start with.

Anyone newly off cigarettes and still working out nicotine strength shouldn't be doing dilution maths on day one. Our nicotine strength guide is a better first stop, and a prefilled pod kit or a straight 10ml nic salt bottle gets a known, consistent strength with zero measuring involved.

People who dislike handling concentrated nicotine at all are also better off avoiding shots. A nic shot at 18mg or 20mg per ml is far more concentrated than the finished vape you'll actually inhale, and while the risk from ordinary consumer use is low when it's handled sensibly, there's no reason to introduce that step if you'd rather not. Anyone who wants a completely mess-free format, no pouring, no shaking, no headroom to think about, is simply better served by prefilled pods or ready-mixed bottles.

And if you only vape occasionally, the maths stops making financial sense too. A 100ml shortfill plus shots is a bulk buy. If a 10ml bottle lasts you a month, there's little point sitting on 90ml of unused liquid slowly losing flavour on a shelf.

How Shortfills Compare to the 2ml/10ml Prefilled Pod System

It's easy to assume shortfills and prefilled pod kits run on the same legal logic, since both eventually involve a 10ml figure somewhere. They don't, and conflating them causes confusion.

Prefilled pod kits work under a completely different part of TRPR: the pod itself, as a sealed tank, can't hold more than 2ml of nicotine e-liquid, and any nicotine-containing refill bottle sold alongside it is capped at 10ml. Nicotine strength in that system is fixed from the moment the pod or refill bottle is filled at the factory, typically at 10mg or 20mg/ml, and you buy it ready to use. We've written about that system in full in Understanding the 2ml + 10ml Vape System in the UK, and it's worth reading if you want the pod-kit side explained properly rather than repeated here.

A shortfill doesn't touch the 2ml or 10ml nicotine-container limits at all, because it isn't a nicotine-containing product until you make it one at home. Nothing about the finished strength is fixed until you decide how many shots to add. That's the real distinction: prefilled pods are a closed, factory-set nicotine system built around 2ml and 10ml caps on nicotine liquid; shortfills are an open, self-mixed system that stays legal precisely because the bottle you buy first contains no nicotine at all. Both routes end up compliant with the same 20mg/ml ceiling once nicotine is present, but they get there through different mechanisms, and neither is "more legal" than the other. For general strength guidance that applies across both formats, see What Nicotine Strength Should You Choose in the UK and the wider legal context in Why UK Vape Laws Limit Nicotine to 20mg.

Safe Mixing Practice for Shortfill E-Liquid and Nic Shots

Mixing your own e-liquid is routine and widely done across the UK, but a nic shot is still a concentrated nicotine product and deserves a bit of care.

Keep nic shots and unmixed shortfills well out of reach of children and pets, in a closed cupboard rather than a work surface or bag pocket. Nicotine in concentrated form is genuinely unpleasant if ingested, and child-resistant caps are a legal requirement on nicotine-containing bottles for exactly this reason, not a nice-to-have. Don't decant a shot into an unlabelled container, and don't leave a part-mixed shortfill somewhere a child could mistake it for a drink or sweets, particularly with brightly flavoured ranges.

When you mix, remove the cap and nozzle from the shortfill bottle, pour the shot or shots in fully, replace the cap tightly, then shake the bottle firmly for around a minute so the nicotine disperses evenly through the liquid. An uneven mix means some vapes hit harder than others from the same bottle, which is more of a nuisance than a safety issue, but it's easy to avoid with a proper shake. Some vapers like to let a freshly mixed shortfill rest, sometimes called steeping, for a day or two before use, particularly with darker or more complex flavours, since flavour compounds can settle and round out slightly over time. This step is optional and won't affect the nicotine strength either way, it's a flavour preference, not a compliance point.

Store mixed and unmixed bottles upright, away from direct heat or sunlight, and use them within a reasonable time once mixed, since flavour and throat feel can drift as a bottle ages. If a shot bottle's seal looks damaged or the cap doesn't click as a child-resistant closure should, don't use it, and treat it the same way you'd treat any damaged nicotine product.

Compliance and Safety: Shortfill E-Liquids and Nic Shots Under UK Law

This is a product category for adults aged 18 and over who already smoke or vape. It is not intended for anyone under 18, for non-smokers, or for non-vapers, and nothing in this article should be read as encouragement to start.

Nicotine is an addictive substance. Nic shots, and any shortfill mixed with one, contain nicotine and should be treated accordingly. Vaping is intended as an option for existing adult smokers and vapers, not presented here as a guaranteed way to quit smoking, and this article makes no medical claims of any kind.

On the legal side: the 20mg/ml maximum nicotine strength, the 2ml tank cap, and the 10ml nicotine-containing refill container limit are all set out in Regulation 36 of the Tobacco and Related Products Regulations 2016, viewable directly on legislation.gov.uk. Nic shots sold by Vape Desires are designed for legal UK sale as TRPR-compliant nicotine-containing products, sold in 10ml bottles at or under the 20mg/ml cap. Shortfill e-liquids are 0mg nicotine at the point of sale and, as such, sit outside the nicotine-specific provisions of TRPR, falling instead under general consumer product safety law rather than the vape-specific nicotine rules covered above. MHRA notification, where it applies, is a nicotine-containing product requirement; genuinely 0mg shortfills are not required to appear on the MHRA's notified product register, though the nic shot you add should be. You can check a product's MHRA notification status directly through the MHRA's own e-cigarette portal if you want to verify a specific shot before buying. Where a specific product's individual MHRA notification cannot be confirmed against that register at the time of writing, that should be treated as needs confirmation rather than assumed.

Only use nic shots and shortfills together in the combinations they're designed for, and don't exceed 20mg/ml in any finished mix, both because it's the legal limit and because concentrations above that aren't something UK-regulated nic shots are designed to reach in the first place. Reusable vaping formats, including shortfills, nic shots, prefilled pods and refillable tanks, remain legal in the UK. Single-use disposable vapes do not; they were banned from sale from 1 June 2025 under environmental regulations covering England, with equivalent rules in Scotland, Wales and Northern Ireland (see GOV.UK: ditch single-use vapes as ban deadline looms). That ban isn't really this article's subject, but it's part of why the shortfill-plus-nic-shot format has grown in relevance: it's a reusable, refillable system that was never affected by it.

Recycle empty bottles responsibly through your local household recycling scheme where plastics are accepted, and dispose of any leftover nicotine liquid the way you would other household chemical waste rather than pouring it down a drain.

Shortfill and Nic Shot FAQs

1. Are shortfill e-liquids legal in the UK?
   Yes. Shortfills are sold at 0mg nicotine, which places them outside the nicotine-specific limits in TRPR, including the 10ml container rule. They're regulated instead under general consumer product safety law. The nic shot added afterwards is the part that has to comply with TRPR's nicotine rules directly.
   
   
2. Is a nic shot the same thing as a nicotine salt e-liquid?
   Not quite. A nic salt shot uses nicotine salt chemistry and is usually 50VG/50PG, built to go into a shortfill for pod kit use. A freebase nic shot is usually 100% VG and goes into a high-VG shortfill for sub-ohm or DTL tanks. Both are still "nic shots" in the general sense, just built for different bases and devices.
   
   
3. How much nicotine is in a finished shortfill mix?
   It depends entirely on how many shots you add and how big the finished bottle is. Use the formula: (shot strength in mg/ml x shot volume in ml x number of shots) divided by total finished volume in ml. See the worked examples above for three real calculations.
   
   
4. Can I get a 20mg/ml mix from a shortfill?
   Not realistically with standard bottle sizes. Even a strong mix, two 20mg shots into a small 40ml base, only reaches around 6.67mg/ml once topped up. To get near 20mg/ml you'd need to buy a pre-mixed 10ml nic salt bottle instead, rather than trying to force it through a shortfill.
   
   
5. Do I need to shake a shortfill after adding a nic shot?
   Yes. Shake it firmly for around a minute so the nicotine disperses evenly through the liquid. Skipping this can leave some vapes from the same bottle noticeably stronger or weaker than others.
   
   
6. Should I let a mixed shortfill steep before vaping it?
   It's optional. Some vapers rest a freshly mixed bottle for a day or two so the flavour settles, particularly with darker or dessert-style profiles. It won't change the nicotine strength either way, it's purely a flavour preference.
   
   
7. Which VG/PG ratio should I buy for my pod kit?
   A 50/50 shortfill, paired with a nic salt shot, is the standard match for pod kits and MTL devices. A 70/30 or 80/20 high-VG shortfill, paired with a freebase shot, suits sub-ohm tanks and DTL devices instead. Using the wrong ratio in your device tends to cause leaking, weak flavour or a coil that struggles to wick.
   
   
8. Is a shortfill cheaper than buying pre-mixed 10ml nic salt bottles?
   Usually, per ml, yes, since you're buying a much larger volume of base liquid in one go and only paying separately for the nicotine shots. It only works out cheaper in practice if you actually get through that much liquid before flavour and strength start to drift with age.
   
   
9. Do shortfills need MHRA notification?
   No, not the shortfill itself, since it's 0mg nicotine and falls outside TRPR's nicotine-containing product notification requirement. The nic shot you add is a nicotine-containing product and should be. You can check notification status for a specific product through the MHRA's e-cigarette portal; where this can't be confirmed for a specific item, treat it as needs confirmation.
   
   
10. Can I use a freebase shot in a 50/50 shortfill by mistake, and is it dangerous?
    It won't put you over the legal nicotine limit and it isn't dangerous in the way of being unsafe to use, but it's not the intended match. A freebase shot in a thinner 50/50 base built for MTL pod kits often gives a harsher throat hit than expected, since freebase nicotine tends to feel stronger on the throat than salt nicotine at an equivalent strength.

Buying the Right Shortfill and Nic Shot Combination

The decision genuinely comes down to two things: which VG/PG ratio matches your device, and which nicotine format, freebase or salt, suits your throat and your target strength. Get those two right and the rest is arithmetic, not guesswork.

If you're running a pod kit, start with a 50/50 shortfill and a nic salt shot, and use the worked examples above to land somewhere around 3mg to 4mg/ml unless you know you want stronger. If you're running a sub-ohm tank, a 70/30 shortfill with a freebase shot at a lower finished strength, closer to 1.8mg to 3mg/ml, will generally match what a DTL setup is built to deliver comfortably. Browse the current range, check the FAQs page for anything not covered here, and if you want the research and compliance checking behind this guide, that sits with Callum Reid on the about us page.