Nicotine Strength Explained: mg/mL, Nic Salt Labels and the NZ Limits
The nicotine figure on an e-liquid label is the most commonly misread number in vaping. The same bottle can be described as "25 mg", "2.5%" or "14.26 mg/mL nicotine" depending on which figure is being quoted. This page explains what each one means and how New Zealand requires them to be shown. It is current as at September 2026.
The unit
Nicotine strength is a concentration: milligrams of nicotine per millilitre of liquid. A 30 mL bottle at 12 mg/mL contains 360 mg of nicotine in total.
New Zealand requires the nicotine concentration to be shown on the container label in mg/mL. A percentage on its own is not sufficient.
Percentages and mg/mL
Overseas labels often use percentages. Because e-liquid has a density close to 1 g/mL, 1% is approximately 10 mg/mL. So 2% is about 20 mg/mL and 5% is about 50 mg/mL.
Why a nicotine salt label can show two numbers
In a nicotine salt e-liquid, the nicotine is bonded to an acid, commonly benzoic acid. The salt weighs more than the nicotine within it, so a label can state either the concentration of the salt or the concentration of the nicotine, and the two figures are different.
The nicotine figure is roughly 0.57 times the salt figure. A liquid described as 25 mg/mL of nicotine salt contains about 14.3 mg/mL of nicotine. One described as 50 mg/mL of nicotine salt contains about 28.5 mg/mL of nicotine.
This is the ambiguity the Ministry of Health resolved in 2023. The original regulation set a 50 mg/mL limit for nicotine salts, which was read by some as 50 mg/mL of nicotine. The clarified rule expresses the limit as 28.5 mg/mL of nicotine, which corresponds to 50 mg/mL of nicotine salt. A product marked "50 mg" or "5%" is quoting the salt figure at the New Zealand maximum, not a product above the limit.
The legal maximums in New Zealand
| E-liquid type | Maximum |
|---|---|
| Freebase nicotine | 20 mg/mL of nicotine |
| Nicotine salt | 28.5 mg/mL of nicotine (50 mg/mL of nicotine salt) |
In addition, a container of vaping substance sold at retail may contain no more than 1,800 mg of nicotine in total, and may not exceed 120 mL unless it is nicotine-free.
Strengths by device type
- Sub-ohm tanks (direct-to-lung): freebase e-liquid at lower strengths. Higher concentrations are harsh at these power levels.
- Refillable pod systems (mouth-to-lung): nicotine salt e-liquid across the available range, or freebase at the upper end of its range.
- Prefilled pods: supplied at whatever strength the pod manufacturer produces, commonly at or near the nicotine salt maximum.
- Nicotine-free: 0 mg/mL e-liquid is also available.
Comparing two products
- Find the mg/mL figure. If the label gives only a percentage, multiply by 10.
- For a nicotine salt product, establish whether the figure quoted is the salt or the nicotine. If only the salt figure is shown, multiply by roughly 0.57.
- Compare nicotine to nicotine. A bottle marked "25 mg salt" contains about 14 mg/mL of nicotine, which is less than an 18 mg/mL freebase bottle despite the larger number on the front.
What else a compliant label shows
Alongside the nicotine concentration, a container of vaping substance sold in New Zealand must carry the bilingual nicotine warning, the prescribed safety messages, the ingredients and their quantities, the volume, a batch number, the manufacturer's contact details, an expiry date, the PG:VG ratio, and a variant name drawn from the approved flavour names in the Regulations. How to check a vaping product is legal in NZ covers this in full.
Related reading
Sources: Smokefree Environments and Regulated Products Regulations 2021, Schedule 5; Ministry of Health, Proposed regulation to clarify allowable nicotine concentration for some vaping products, 12 June 2023.