September 8, 2026

How Many Nic Shots Should You Add to a Shortfill?

The number of nic shots you need depends on your shortfill size and the nicotine strength you want. This guide gives you a complete reference table for every common bottle size and target strength, with the formula behind the numbers explained clearly.

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Quick answer: Add one 18mg nic shot to a 50ml shortfill for 3mg. Add two 18mg nic shots to a 100ml shortfill for 3mg. To reach 6mg in a 50ml shortfill you need two shots but must first remove 10ml of the base liquid to create space. Do not add more shots than the bottle has headspace for. 3mg is the standard target strength for sub-ohm vaping and the level most shortfills are designed around.

The Complete Nic Shot Reference Table

The table below shows how many 18mg nic shots to add for the most common shortfill sizes and target strengths. Where you need to decant liquid first to create space, this is noted clearly.

Shortfill Size	Bottle Size	Target Strength	18mg Shots Needed	Final Volume	Notes
50ml	60ml	0mg	0	50ml	Vape as-is, nicotine free
50ml	60ml	3mg	1	60ml	Standard setup, fits perfectly
50ml	60ml	6mg	2	70ml	Remove 10ml first to create space
100ml	120ml	0mg	0	100ml	Vape as-is, nicotine free
100ml	120ml	1.5mg	1	110ml	Half-strength option
100ml	120ml	3mg	2	120ml	Standard setup, fits perfectly
100ml	120ml	6mg	4	140ml	Remove 20ml first, use large empty bottle
200ml	250ml	3mg	4	240ml	Fits in headspace of most 250ml bottles

Important: Only add nic shots if the bottle has sufficient headspace. Overfilling the bottle makes it impossible to shake properly and risks spillage of concentrated nicotine. If you want a higher strength than 3mg from a standard shortfill, decant the excess base liquid into a clean empty bottle before adding extra shots.

How the Maths Works

You do not need to use a calculator for the standard setups. The formula below explains why the numbers in the table work the way they do, which helps if you encounter a non-standard bottle size.

The Formula Final strength (mg) = (Shot strength x Number of shots x 10) divided by (Shortfill volume + Shot volume) Example: 1 x 18mg shot added to 50ml shortfill = (18 x 1 x 10) divided by (50 + 10) = 180 divided by 60 = 3mg Example: 2 x 18mg shots added to 100ml shortfill = (18 x 2 x 10) divided by (100 + 20) = 360 divided by 120 = 3mg

The principle is simple: the nic shot dilutes as it mixes into the much larger volume of shortfill base. One 18mg shot in 50ml of base produces 60ml total, where the nicotine is now spread across six times the volume it started in. One sixth of 18mg is 3mg. The formula scales perfectly regardless of bottle size as long as the ratio of shortfill to shots remains the same.

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What Happens If You Add Too Many Shots

Adding more nic shots than the bottle has headspace for causes two problems. First, you cannot fit the extra liquid in without overfilling the bottle, which makes shaking correctly impossible. Second, adding extra shots dilutes the flavour concentration of the shortfill beyond the level the manufacturer intended. Shortfill manufacturers pre-concentrate their flavourings to account for the dilution caused by the standard number of shots. Adding more shots than intended dilutes the flavour further, producing a noticeably weaker result.

The practical maximum nicotine strength achievable in a standard shortfill without decanting is 3mg for a 50ml shortfill and 3mg for a 100ml shortfill. To reach 6mg you need to remove liquid from the bottle first. Going beyond 6mg in a shortfill is not recommended because the flavour dilution at that point becomes significant enough to affect the vaping experience noticeably. Vapers who need more than 6mg are better served by pre-mixed 10ml e-liquids at their required strength.

Using 20mg Nic Shots Instead of 18mg

Some nic shots are sold at 20mg rather than 18mg. The difference in final strength is small but worth understanding if you use them.

Shortfill Size	Shot Strength	Shots Added	Final Strength
50ml	18mg	1	3.0mg
50ml	20mg	1	3.3mg
100ml	18mg	2	3.0mg
100ml	20mg	2	3.3mg

The difference between 18mg and 20mg shots produces a final strength of 3mg versus 3.3mg at the standard one-shot-per-50ml ratio. This is a negligible difference for most vapers. Use whichever is available or offers better value. The important thing is to be consistent so your experience stays predictable from bottle to bottle.

For a full explanation of what nic shots are, the difference between freebase and nic salt shots and the step-by-step mixing process, read our guide to What Is a Nic Shot and How Do You Mix It? The full Celtic Vapours Shortfill Guide covers every aspect of shortfill vaping.

Frequently Asked Questions

Do I have to add a nic shot to my shortfill? No. Shortfills are perfectly fine to vape at 0mg without adding any nic shots. If you are a nicotine-free vaper or you have reduced your intake to zero, simply vape the shortfill as it comes. The bottle will be slightly less than full but this does not affect the vaping experience in any meaningful way.

Can I add half a nic shot for a lower strength? Yes. If 3mg is too strong for you, adding half a 10ml nic shot (5ml) to a 50ml shortfill produces approximately 1.5mg in 55ml of final liquid. Some vapers stepping down from higher strengths find this useful as an intermediate level. Use a small measuring syringe or carefully pour half the nic shot into the shortfill and reseal the nic shot bottle for later use.

Why does my shortfill only have room for one nic shot? A standard 50ml shortfill in a 60ml bottle has exactly 10ml of headspace, which fits one 10ml nic shot for a 3mg result. This is by design. The manufacturer has sized the bottle and headspace specifically for the standard one-shot mixing ratio. If you want more than 3mg from a 50ml shortfill, you need to remove some of the base liquid first to create additional headspace for a second shot.

Does the brand of nic shot matter? No, within reason. Nic shots are unflavoured and their primary ingredient is pharmaceutical-grade nicotine in a PG or VG base. Any reputable UK-manufactured or MHRA-registered nic shot at the right strength and VG:PG ratio will mix correctly with any shortfill. Match the VG:PG ratio of the shot to your shortfill for the best result. Brand compatibility is not a concern.

What strength do most shortfill vapers use? 3mg is by far the most popular target strength for shortfill vapers in the UK. It is the standard the majority of shortfill manufacturers design their bottle sizes and headspace around. Sub-ohm devices compensate for the lower concentration by producing high vapour volume per puff, which delivers a satisfying total nicotine intake per session even at 3mg.