Shortfills are one of the most popular formats for vape juice in the UK. They provide excellent value, plenty of flavour variety, and the flexibility to add your own nicotine shots. A common question among vapers is how strong you can make a 100ml shortfill. The answer depends on how many nic shots you add, what strength those shots are, and how much space is left in the bottle.
Why 100ml shortfills come nicotine-free
UK law under the Tobacco Products Directive restricts the sale of nicotine-containing e liquid bottles to a maximum size of 10ml. This is why all 100ml shortfills are sold nicotine-free. The bottle is usually filled short, leaving space for two 10ml nic shots. Once you add the shots and shake the bottle, you have a ready-to-vape liquid at the nicotine strength you choose.
This system has become the standard way vapers enjoy larger bottles without breaking the law, offering both flexibility and better value compared to buying ten small bottles. If you want to see the wide variety of flavours available, explore our 100ml vape juice collection which has options across fruity, dessert, soda, and candy categories.
How strong can a 100ml shortfill be?
Most nic shots are sold at 18mg strength. When you add them to a 100ml shortfill, the nicotine is diluted across the larger bottle.
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Adding one 18mg nic shot creates a final strength of around 1.5mg.
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Adding two 18mg nic shots creates a final strength of around 3mg.
This is the standard maximum for 100ml shortfills because the bottles are usually 120ml in total. With 100ml of liquid already inside, there is only space for two 10ml nic shots. That means 3mg is the strongest practical option for most shortfills.
Can you make shortfills stronger than 3mg?
Technically, yes, but it requires workarounds. Some vapers choose to remove a small amount of liquid from the bottle before adding extra nic shots. By creating more space, you can add three or even four shots, but this dilutes the flavour and can alter the balance of the juice.
For example:
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Adding three shots to a 100ml base would raise the strength to around 4.5mg.
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Adding four shots would push it to about 6mg.
However, most shortfills are not designed for this, and the flavour may not taste as intended. For those who want higher nicotine strengths, nic salts in 10ml bottles remain the better option, as they are designed to deliver 10mg or 20mg strengths without compromising flavour.
Why 3mg works for sub ohm vaping
Many vapers wonder why shortfills cap out at around 3mg, but this strength actually suits sub ohm devices perfectly. Sub ohm kits produce larger clouds and deliver more vapour per puff, which means you absorb more nicotine even at lower strengths. A 3mg shortfill often feels equivalent to a much higher strength in a small pod device.
This is why 100ml shortfills are most popular with sub ohm vapers. They provide smooth flavour, plenty of vapour, and a low but satisfying nicotine hit. For those who want stronger nicotine levels, smaller nic salt bottles are usually the preferred choice.
Nic shot alternatives
If you want more flexibility in strength, you can experiment with different types of nic shots. Most are 18mg freebase, but there are also nic salt shots available at 20mg. These deliver a smoother hit and may feel stronger even if the final mg calculation is similar. Some vapers prefer nic salt shots because they create less throat harshness at higher levels.
For example, two 20mg nic salt shots added to a 100ml shortfill would still only create around 3.3mg strength, but the effect may feel stronger and smoother compared to standard freebase shots.
Why shortfills remain the best value
Even with a maximum strength of 3mg, shortfills remain the most cost-effective way to vape. At £10 for 100ml with two free nic shots included, they provide thousands of puffs at a fraction of the cost of buying smaller bottles. They also give you consistency of flavour across 100ml, something you do not get when constantly switching between 10ml bottles.
If you are new to shortfills and want clear instructions on how to add nic shots and calculate strength, our 100ml shortfill guide explains the process step by step.
Final thoughts
The strongest nicotine option for a 100ml shortfill is usually 3mg, achieved by adding two 18mg nic shots to the 100ml base. While it is possible to add more shots by removing some liquid, this dilutes flavour and is not how shortfills are designed to be used. For higher nicotine levels, nic salts in 10ml bottles are the better choice.
Shortfills remain the most popular format for regular vapers because they provide unbeatable value, smooth flavour, and enough nicotine strength for sub ohm devices. Whether you want to vape nicotine-free, 1.5mg, or 3mg, 100ml bottles give you the flexibility to choose, making them a staple for anyone who enjoys big clouds and bold flavours.
If you are choosing shots and want to know when you even need them, start with Do You Need Nic Shots with 100ml Vape Juice?. For a clean step by step method that avoids dilution errors, keep how to add nicotine to vape juice open while you mix.