What Is a Shortfill E-Liquid?
A shortfill is a bottle of 0mg e liquid that is not filled to the top. The empty headspace exists specifically so you can pour in a nic shot, a small bottle of unflavoured concentrated nicotine, and shake the two together to create nicotine containing e liquid at your chosen strength. A 60ml bottle holding 50ml of e liquid is a "50ml shortfill." A 120ml bottle holding 100ml of liquid is a "100ml shortfill." The gap is deliberate, sized to take exactly the number of nic shots the brand intends.
Shortfills exist because of a specific piece of UK regulation, not because manufacturers wanted a bigger bottle for its own sake.
Why Do Shortfills Exist? The TPD Rule Behind Them
Under the Tobacco and Related Products Regulations 2016 (TRPR, the UK's implementation of the EU's TPD), any single bottle of e liquid containing nicotine is capped at 10ml. That is a hard legal limit, it applies regardless of nicotine strength, brand, or retailer.
E liquid manufacturers wanted to sell larger format bottles, both because bigger bottles are cheaper to produce per ml and because heavier vapers do not want to buy ten separate 10ml bottles a week. The workaround: sell the large bottle with zero nicotine in it. A 0mg e liquid is not covered by the 10ml cap at all, so it can legally be sold in 50ml, 100ml, or 200ml formats. You then add your own nicotine at home, using a separately regulated nic shot (which is itself capped at 10ml, but sold empty of flavour, purely as a nicotine concentrate).
This is entirely legal and is how the vast majority of large bottle e liquid is sold in the UK. It is a genuine regulatory workaround, not a grey market trick, every shortfill and nic shot sold by a legitimate UK retailer is TPD notified and MHRA registered the same as any 10ml bottle.
Shortfill and Nic Shot Sizes Explained
| Format | Bottle size | Liquid inside | Headspace for nic shots |
|---|---|---|---|
| 50ml shortfill | 60ml bottle | 50ml of 0mg e liquid | 10ml, exactly one standard nic shot |
| 100ml shortfill | 120ml bottle | 100ml of 0mg e liquid | 20ml, exactly two standard nic shots |
| 200ml shortfill | 240ml bottle | 200ml of 0mg e liquid | 40ml, exactly four standard nic shots |
| Nic shot | 10ml bottle | 10ml of concentrated nicotine, no flavour, typically 18mg freebase or 20mg nic salt | N/A, this is what gets added |
The pattern holds across every size: the bottle is always exactly 20% bigger than the stated shortfill size, and that 20% headspace is precisely enough room for one nic shot per 50ml of shortfill liquid.
How to Mix a Shortfill and Nic Shot: Step by Step
- Remove the cap and nozzle from both the shortfill bottle and the nic shot bottle. Shortfill bottles use a pressure fit nib that needs to come out before anything else fits inside.
- Check the VG/PG ratio on both bottles. They do not have to be identical, but matching them keeps the final consistency predictable.
- Empty the entire nic shot into the shortfill bottle. For a 50ml shortfill, that is one 10ml shot. For a 100ml shortfill, that is two.
- Replace the nib and cap, then shake the bottle for one to two minutes. This is not optional, nicotine needs proper agitation to distribute evenly through the liquid.
- Optional: leave the bottle to steep for 24 to 48 hours in a cool, dark place. Steeping is not required to make the liquid safe or usable, but many vapers find flavour develops over the first day or two.
- Vape as normal. Once mixed and shaken, the e liquid behaves exactly like a pre mixed nic salt or freebase bottle at the same strength.
The Shortfill Nicotine Maths: Exactly How Strength Is Calculated
This is the part most shortfill guides gloss over with a calculator widget instead of showing the actual arithmetic. Here is the working.
Standard 50ml setup:
50ml of 0mg e liquid plus one 10ml nic shot at 18mg/ml. The nic shot contains 10ml x 18mg = 180mg of total nicotine. Once mixed, that 180mg is spread across the full 60ml of combined liquid (50ml + 10ml), giving 180mg divided by 60ml = 3mg/ml. That is why 3mg is the standard shortfill strength, it is simply what one full strength nic shot dilutes to across the standard bottle size.
Standard 100ml setup:
100ml of 0mg e liquid plus two 10ml nic shots at 18mg/ml. Total nicotine: 2 x 10ml x 18mg = 360mg. Total liquid: 100ml + 20ml = 120ml. Strength: 360mg divided by 120ml = 3mg/ml. Same result, because the ratio of shortfill to nic shot stays constant at 5 to 1 regardless of bottle size.
Wanting a stronger mix, for example 6mg/ml.
You need double the nicotine relative to the same liquid volume. Since a standard shortfill only leaves room for one shot per 50ml, hitting 6mg means decanting some of the 0mg liquid out first to make room for a second shot: pour off 10ml from your 50ml shortfill (down to 40ml), then add two 18mg nic shots (20ml). Total nicotine: 2 x 180mg = 360mg. Total liquid: 40ml + 20ml = 60ml. Strength: 360mg divided by 60ml = 6mg/ml.
Wanting a lighter mix, for example 1.5mg/ml.
Use half a nic shot instead of a full one. Half of 10ml at 18mg = 90mg nicotine. Added to 50ml of shortfill: total liquid 55ml, strength 90mg divided by 55ml = 1.6mg/ml, close enough to the 1.5mg target that most vapers round to it in practice.
Using nic salt shots instead of freebase.
UK nic salt shots are typically sold at 20mg rather than 18mg. One 20mg nic salt shot in a 50ml shortfill: 10ml x 20mg = 200mg nicotine, across 60ml total, gives 200mg divided by 60ml = 3.33mg/ml, slightly stronger than the standard freebase setup at the same one shot ratio.
Why 6mg Is Roughly the Practical Ceiling for Shortfill Mixing
Every additional nic shot dilutes the flavour further, since nic shots carry no flavouring of their own, they are pure nicotine base. At 3mg (one shot per 50ml), flavour dilution is barely noticeable. Push to 6mg (two shots per 50ml, after decanting) and the flavour is audibly thinner, most vapers describe it as "flatter" rather than weaker in throat hit. Beyond 6mg, the maths still works, but the amount of decanting and extra shots required means you are diluting the shortfill's actual flavour concentrate so heavily that most of what you are tasting is nic shot base rather than the flavour you paid for. If you need higher than 6mg regularly, a pre mixed 10ml nic salt bottle at 10mg or 20mg is a more efficient route than fighting a shortfill's design toward a strength it was not built for.
VG/PG Ratio: Why It Matters More Than Brand Matching
Every e liquid, shortfill or 10ml bottle, is a mix of vegetable glycerin (VG) and propylene glycol (PG). The ratio changes how the liquid behaves, not how it is flavoured.
PG carries flavour more sharply and produces a stronger throat hit, but less visible vapour. VG is thicker, produces bigger clouds, and gives a smoother, milder throat hit.
Shortfills are typically formulated high VG, 70/30 or 80/20 VG/PG, built for the sub ohm tanks most shortfill buyers are using. Some brands, including 50/50 shortfills aimed at pod kit users, exist specifically for lower power devices that cannot handle thick high VG liquid without dry hits.
The rule that actually matters: match your nic shot's VG/PG ratio to your shortfill's ratio, not necessarily its brand. A 70/30 shortfill with a 70/30 nic shot mixes predictably. A 100% VG nic shot added to a 70/30 shortfill shifts the final ratio higher VG than intended, which can be too thick for the coil the shortfill was designed around. Nic shots are nicotine only, with no flavouring, so cross brand mixing is fine as long as the VG/PG ratio and nicotine type (freebase vs nic salt) match what you are adding it to.
Shortfill VG/PG Ratios and What Device They Suit
| VG/PG ratio | Typical use | Suits |
|---|---|---|
| 50/50 | Lower power pod kits and MTL devices | Vapers using refillable pod systems who want shortfill pricing without a sub ohm tank |
| 70/30 | The most common shortfill ratio | Balanced flavour and cloud, works across most sub ohm tanks and higher power pod kits |
| 80/20 or higher VG | Maximum cloud production | Dedicated sub ohm and cloud chasing setups, too thick for most pod kits without dry hits |
A genuine failure mode worth naming: putting a high VG (80/20 or 100% VG) shortfill into a low power pod kit is one of the most common shortfill mistakes. The liquid is too thick to saturate a small pod coil fast enough, which causes dry hits, a burnt taste from the first few puffs, not gradually over time. If you are using a refillable pod kit rather than a sub ohm tank, check the shortfill's VG/PG ratio before buying, not after the coil's already burnt out.
Freebase Nic Shots vs Nic Salt Shots: Which Should You Use?
Standard nic shots use freebase nicotine, typically 18mg, matched to shortfills built for sub ohm and higher power devices, where 3mg freebase feels smooth.
Nic salt shots, usually 20mg, are also available for mixing into shortfills, but they are a less common pairing. Nic salts are formulated to feel smooth at high strength in low power MTL devices, mixing a nic salt shot into a high VG, sub ohm oriented shortfill somewhat defeats the purpose, you would typically be better off buying a pre mixed 50/50 nic salt shortfill designed for a pod kit, or simply using a pre mixed 10ml nic salt bottle instead. Our nic salt strength guide covers how to choose between 5mg, 10mg and 20mg if you go that route.
If you are vaping a shortfill in a sub ohm tank, stick with freebase nic shots. If you specifically want a shortfill sized bottle for an MTL pod kit, look for a 50/50 shortfill paired with a nic salt shot rather than mixing salts into a standard high VG shortfill.
Shortfills, Nic Shots and the New UK Vape Duty From 1 October 2026
This is the single biggest thing changing for shortfill buyers in 2026, and it is the reason this format is worth reconsidering if cost matters to you.
From 1 October 2026, HMRC's Vaping Products Duty applies a flat rate of £2.20 per 10ml of vaping liquid, confirmed on the government's own policy page, regardless of nicotine strength. That includes the 0mg shortfill liquid itself, the duty applies to volume, not nicotine content, so a 0mg shortfill picks up exactly the same duty per ml as a 20mg nic salt bottle. VAT applies on top of the duty, bringing the real increase closer to £2.64 per 10ml.
Because shortfills are large format by definition, the duty compounds fast:
| Format | Volume | Duty (pre VAT) | Duty (with VAT, approx.) |
|---|---|---|---|
| 50ml shortfill (0mg liquid only) | 50ml | £11 | £13.20 |
| 100ml shortfill (0mg liquid only) | 100ml | £22 | £26.40 |
| Each 10ml nic shot, added separately | 10ml | £2.20 | £2.64 |
| Full 50ml shortfill plus 1 nic shot | 60ml | £13.20 | £15.84 |
| Full 100ml shortfill plus 2 nic shots | 120ml | £26.40 | £31.68 |
Compare that to a 2ml prefilled pod, covered in detail in our prefilled pod kit buying guide, which only picks up 44p in duty (about 53p with VAT) regardless of puff count, because TPD already caps a pod at 2ml. Industry estimates put the overall cost increase on standard prefilled pods at around 7%, against up to 147% on a full 100ml shortfill setup with two nic shots, since the duty is levied strictly on volume and shortfills are, by design, the largest volume format on the market.
That does not mean shortfills stop making sense after October 2026, they are still likely to be cheaper per ml than premium 10ml bottles even with the duty added, since the underlying liquid cost per ml was so much lower to start with. But the gap narrows sharply, and if you are a heavy vaper who buys 100ml bottles specifically to save money, it is worth running your own numbers against a refillable pod kit or even a prefilled kit before assuming shortfills remain the cheapest route.
Is It Worth Buying Shortfills Before October 2026?
E liquid bought before 1 October 2026 carries no duty at all, and correctly stored, unopened e liquid typically lasts one to two years, some vapers extend that further by freezing unopened bottles, though quality can shift over long term storage regardless of method. If you know your regular flavours and strengths and have the storage space, buying a few extra shortfills and nic shots ahead of the deadline is a straightforward way to delay the price increase, particularly on 100ml formats where the duty hit is largest in absolute terms.
This is not a recommendation to panic buy, it is simply the honest arithmetic: a 100ml shortfill you buy in September 2026 costs the same as it does today, the identical bottle bought in November 2026 costs roughly £22 more before VAT.
Shortfill and Nic Shot Buying Guide: The Suitability Matrix
| Your situation | Recommended setup | Why | Wrong for |
|---|---|---|---|
| Heavy sub ohm vaper, wants the lowest cost per ml | 100ml shortfill (70/30 or 80/20 VG) plus 2 freebase nic shots | Largest format, lowest per ml cost even after October 2026 duty | Pod kit users, the high VG ratio will cause dry hits |
| Pod kit user who still wants shortfill size bottles | 50/50 shortfill plus matching ratio nic shot | Thin enough to saturate a small pod coil without dry hits | Sub ohm tank users, will feel underpowered on flavour and cloud |
| Wants maximum flavour, minimum nicotine dilution | Single nic shot per 50ml (3mg/ml), not decanting for extra shots | Every added shot dilutes flavour further, 3mg keeps dilution minimal | Heavy smokers needing higher nicotine, 3mg likely will not be enough for a 15+ a day habit |
| Ex smoker wanting a stronger mix than 3mg | Decant and double up to 6mg, or switch to a pre mixed 10ml nic salt bottle instead | 6mg is close to the practical ceiling before flavour dilution becomes obvious | Anyone happy at 3mg, no need to complicate the mix |
| Buying ahead of the October 2026 duty | Stock up on 100ml formats specifically | Largest absolute duty saving per bottle | Anyone without cool, dark storage space for multiple bottles over a year |
Common Mistakes People Make Mixing Shortfills
Adding a nic shot to e liquid that already contains nicotine.
Always check the shortfill bottle is genuinely 0mg before adding a shot. Adding nicotine to an already nicotine liquid creates an over strength mix with no reliable way to know the real final strength.
Mismatching VG/PG ratios.
A 100% VG nic shot in a 70/30 shortfill shifts the final liquid thicker than intended, which can cause wicking problems in coils built for the original ratio.
Using a high VG shortfill in a pod kit.
The single most common cause of dry hits and burnt taste reported by first time shortfill buyers moving from 10ml bottles. Check the ratio before buying, not after the coil's ruined.
Not shaking the bottle for long enough.
A quick five second shake is not sufficient. Nicotine needs proper agitation, one to two minutes minimum, to distribute evenly, an under mixed bottle gives you a weaker than expected first few vapes and a stronger than expected last few.
Assuming steeping is required rather than optional.
Steeping improves flavour development in some profiles, particularly dessert and tobacco, but a properly mixed and shaken shortfill is fully safe and usable immediately. Do not feel you need to wait 48 hours before vaping a fresh mix.
Skin contact with the nic shot itself.
Unlike diluted e liquid, a nic shot is concentrated nicotine. Avoid direct skin contact when pouring, and always store both shortfills and nic shots well out of reach of children and pets, the concentrated form is significantly more hazardous than the diluted mix you end up vaping.
Shortfill and Nic Shot FAQ
Q1 How much nic shot do I need for a 50ml shortfill?
One standard 10ml nic shot, giving you 60ml of e liquid at approximately 3mg/ml nicotine strength.
Q2 How much nic shot do I need for a 100ml shortfill?
Two standard 10ml nic shots, giving you 120ml of e liquid at approximately 3mg/ml.
Q3 Can I use any nic shot with any shortfill?
Nic shots are nicotine only with no flavouring, so mixing brands is generally fine. Match the VG/PG ratio and nicotine type (freebase or nic salt) to your shortfill rather than worrying about brand matching.
Q4 What strength should I aim for when mixing a shortfill?
3mg/ml is the standard result from one nic shot per 50ml and works well for most established vapers. Heavier or newer switchers from smoking may want to decant and use two shots per 50ml for 6mg, the practical ceiling before flavour dilution becomes obvious.
Q5 Do shortfills go off if I don't use the nic shot straight away?
The 0mg shortfill liquid itself keeps for a long time unopened. Once you have added a nic shot and mixed it, treat it the same as any nicotine e liquid, use within a reasonable window and store away from heat and light.
Q6 Is it cheaper to buy a shortfill and nic shot, or a pre mixed 10ml bottle?
Per ml, shortfills are typically significantly cheaper than pre mixed 10ml bottles, even after the October 2026 duty lands, because the underlying liquid cost is lower for large format bottles. The gap narrows after October 2026 but does not close.
Q7 Can I make a shortfill stronger than 6mg?
Yes, by decanting more liquid and adding additional shots, but each shot dilutes flavour further. Beyond 6mg, most vapers find a pre mixed 10ml bottle at the strength they need is a better tasting option than heavily diluting a shortfill.
Q8 What happens to shortfill prices after 1 October 2026?
The Vaping Products Duty adds £2.20 per 10ml of the 0mg base liquid itself, plus £2.20 per 10ml nic shot. A 50ml shortfill plus one shot rises by roughly £13.20 in duty before VAT, a 100ml shortfill plus two shots by roughly £26.40.
Q9 Should I buy shortfills before the October 2026 duty comes in?
If you know your regular flavours and have suitable storage, buying ahead avoids the duty entirely on that stock, since e liquid bought before 1 October 2026 carries no duty and typically stores well for one to two years.
Q10 Can I use a shortfill in a pod kit instead of a sub ohm tank?
Only if it is a 50/50 VG/PG shortfill, matched to a similar ratio nic shot. Standard high VG shortfills (70/30 or higher) are too thick for most pod coils and will cause dry hits.