TPD rules explained: why tanks are 2ml, bottles are 10ml and nicotine stops at 20mg

People still call them the TPD rules, after the EU Tobacco Products Directive they came from. In UK law they sit in the Tobacco and Related Products Regulations, often shortened to TRPR, and the government's consumer guidance sets them out plainly.

There are five that matter to you as a buyer. Tanks and pods can hold 2ml at most. Refill bottles containing nicotine can hold 10ml at most. Nicotine strength is capped at 20mg/ml. Packs must be child-resistant. And nicotine products must be notified to the MHRA.

None of these have changed with the new duty or the disposable ban. They sit underneath everything else, which is why every kit on our shelves looks broadly similar.

The 2ml cap applies to the part of the device that holds liquid, so tanks and pods alike. It is why a sub-ohm tank that could easily be built bigger still holds 2ml when sold in the UK, and why vapers who go through a lot of liquid end up refilling more often than they would like.

It also explains the design of big-puff pod kits. The Lost Mary Nera 30K, for instance, does not get its puff count from a giant tank. It comes with two 2ml pods plus two separate 10ml refill containers, so each part stays inside the rules.

If you want fewer refills, battery size and coil choice matter more than tank size, because the tank is capped. Have a look through our tanks and you will see 2ml right across the range.

The 10ml cap applies to refill bottles that contain nicotine. That is why every nic salt and every freebase nicotine liquid comes in 10ml bottles, and why nicotine shots are 10ml too.

Shortfills are the industry's answer. Because they contain no nicotine, they are not limited to 10ml, so you can buy 50ml or 100ml of liquid in one bottle, with space left to add a 10ml nicotine shot yourself. One 18mg shot in a 50ml shortfill gives you 60ml at about 3mg/ml.

Shortfills still pay the new duty, by the way, so the size advantage is about convenience, not tax. Browse shortfills or 10ml liquids.

No nicotine e-liquid sold in the UK can be stronger than 20mg/ml. That covers nic salts, freebase liquids, prefilled pods and nicotine shots. You will often see 20mg described as the strongest option, and that is why.

Below the ceiling, there is a spread. Nic salts usually come in 10mg and 20mg. Freebase liquids for MTL kits often sit around 6mg to 18mg, and shortfills mixed with a nic shot usually land at 3mg or so for big-cloud tanks.

Nicotine is addictive, so it is worth picking the lowest strength that satisfies you. Explore nic salts if you are on a pod kit.

The last two rules are less visible but just as important. Child-resistant packaging means nicotine bottles have caps you have to push or squeeze to open. Annoying with cold hands, but it is the law for a good reason.

MHRA notification means nicotine products have to be notified to the Medicines and Healthcare products Regulatory Agency before they are sold. It is the paperwork that sits behind every genuine nicotine liquid and device. We explain it properly in MHRA notification and why it matters.

Run through this checklist next time you pick up a bottle or a kit.

The size and strength rules have been around long enough to collect their own folklore. Some of it is out of date, some of it never was true.

The biggest one is that the rules disappeared after Brexit. They did not; they are part of UK law through the TRPR, and the government's consumer guidance still sets them out. The second is that shortfills are a loophole that breaks the rules. They are not: they work within the rules precisely because they contain no nicotine.

Flip the cards to test yourself.

A quick check to make sure the numbers stuck. This one catches out people who mix up the bottle limit with the tank limit, which is easy to do when both rules are about size.

Remember: 2ml is about the device, 10ml is about nicotine bottles, and 20mg/ml is about strength. Keep those three separate in your head and every product on the shelf makes sense. For how these rules sit alongside the newer changes, see the UK vape law timeline.

Those limits apply whatever brand you buy and wherever you buy it in the UK.