How to make vape juice at home: the maths and UK rules
How to make vape juice at home: base, flavour and nic shot, the strength formula with worked mixes, and the UK MHRA and HMRC rules for home mixers.
To make vape juice at home, combine a base of propylene glycol (PG) and vegetable glycerin (VG), a flavour concentrate and, if you use nicotine, a nicotine shot, then shake, label and store the bottle out of reach. Final strength is shot strength times shot volume divided by total volume, so a home mix is never stronger than its shot.
This is an evergreen how-to with one dated rule in it. This desk read the MHRA’s e-cigarette regulations page and HMRC’s Vaping Products Duty guidance on 31 October 2026. Both describe UK rules; nothing here describes US law, and none was read for it.
What do you need to make vape juice at home?
Four parts go in the bottle. PG is the thin carrier that holds flavour and most of the throat; VG is the thick, faintly sweet one that makes the cloud. Our four-part breakdown takes each apart, and the 50/50 versus 70/30 guide says which ratio a given coil will tolerate. Choose flavour concentrates sold for vaping, and where the maker prints a usage rate, follow it rather than a forum’s.
The kit is dull and non-negotiable: nitrile gloves, syringes or a measuring cylinder, empty bottles with child-resistant caps, and labels.
How to make vape juice at home, step by step
- Gloves on, surface clear, children and pets out of the room.
- Choose the finished volume and strength, and work out the shot volume with the formula below.
- Measure the base, or start from a nicotine-free shortfill that already contains it.
- Add flavour concentrate at its maker’s rate.
- Add the nicotine shot last, cap, and shake hard.
- Label with contents, strength and the date, and store it where a child cannot reach it.
The shortest version, and in the UK the one that stays on the right side of HMRC, is a duty-paid shortfill topped up with a duty-paid nic shot. The shortfill bottle is left with room for exactly that.
The strength maths: why a home mix is never stronger than its shot
Milligrams of nicotine come only from the shot. Everything else adds volume, so strength can only fall.
| Mix | Nicotine | Total | Final strength |
|---|---|---|---|
| 50ml shortfill + one 10ml 20mg/ml shot | 200mg | 60ml | 3.3mg/ml |
| 100ml shortfill + two 10ml 20mg/ml shots | 400mg | 120ml | 3.3mg/ml |
| 50ml shortfill + one 10ml 18mg/ml shot | 180mg | 60ml | 3.0mg/ml |
| 40ml shortfill + two 10ml 20mg/ml shots | 400mg | 60ml | 6.7mg/ml |
| 30ml from scratch at 6mg/ml, 20mg/ml shot | 9ml shot = 180mg | 30ml | 6.0mg/ml |
Run it backwards to aim for a strength: shot volume equals target strength times total volume, divided by shot strength. A bottle reaches the shot’s strength only if it is all shot. UK shops cannot sell e-liquid stronger than 20mg/ml, so nothing mixed from legal UK shots goes above it. The same averaging governs blending salt and freebase.
What rules is a home mixer bound by in the UK?
| Rule | What the gov.uk page says | Source |
|---|---|---|
| Refill bottle | Nicotine-containing e-liquid for sale in one refill container: 10ml at most | MHRA |
| Strength | E-liquids restricted to no more than 20mg/ml | MHRA |
| Packaging | Nicotine products or their packaging child-resistant and tamper evident | MHRA |
| Ingredients | Certain ingredients banned, including colourings, caffeine and taurine | MHRA |
| Tanks | Capacity of no more than 2ml | MHRA |
| Notification | E-cigarettes and e-liquids notified to and published by the MHRA before sale | MHRA |
| Mixing | Mixing non-duty-paid liquids is manufacturing that needs HMRC approval, even if not for sale | HMRC |
| Exclusion | Mixing duty-paid liquids, such as a shortfill and a nic shot, is not included | HMRC |
| Duty | A flat £2.20 per 10ml, whether the liquid contains nicotine or not | HMRC |
| Stamps | From 1 April 2027, products outside duty suspension must carry a vaping duty stamp | HMRC |
The MHRA rows are rules on products for sale, not a cap on what an adult mixes in a kitchen. They still shape the bench: they are why shots come in 10ml bottles at 20mg/ml or less. The HMRC row is the one that reaches the kitchen table. HMRC’s page, updated 9 July 2026, is written in the future tense; its 1 October 2026 start date has passed. It lists VG and flavourings among dutiable liquids, so a from-scratch mix needs duty-paid inputs. That page does not say which retail bases are sold duty-paid; ask the seller.
Handling nicotine safely
The NIOSH Pocket Guide to Chemical Hazards lists nicotine’s exposure routes as inhalation, skin absorption, ingestion and skin or eye contact. It advises preventing skin contact and flushing contaminated skin with water immediately. The symptoms it lists include nausea, vomiting, headache, dizziness, confusion, cardiac arrhythmias and convulsions. Swallowing is its own problem, covered in our ingestion piece.
FAQ
How do you make e liquid for a vape with household items?
Nothing in the cupboard replaces the four parts every recipe here starts from: PG, VG, a flavour concentrate sold for vaping and, optionally, a nicotine shot. Kitchen tools are fine; kitchen ingredients are not. UK rules ban colourings, caffeine and taurine from e-liquids on sale, which rules out food colouring and energy drinks as additions to anything you plan to inhale.
Is it legal to make your own vape juice in the UK?
It depends on what goes in. HMRC’s guidance says that since 1 October 2026, mixing non-duty-paid liquids to make vape liquid is manufacturing that needs HMRC approval, even when nothing is sold. It excludes mixing duty-paid liquids, such as a duty-paid shortfill with a duty-paid nicotine shot. That shortfill route is the one a home mixer can rely on.
How do you work out the nicotine strength of a home mix?
Multiply the shot’s strength by the shot’s volume to get milligrams of nicotine, then divide by the total volume of the finished bottle. One 10ml shot at 20mg/ml holds 200mg; in a 60ml bottle that is 200 divided by 60, about 3.3mg/ml. To aim for a strength instead, shot volume is target strength times total volume, divided by shot strength.
Mixed at home or bought sealed, the bottle delivers nicotine, an addictive drug. This bench writes for adults who already vape; if you do not, none of this is a reason to start.