When it comes to e-liquids, the terms "shortfill" and "longfill" can be confusing for new vapers. Both refer to specific bottle formats designed around nicotine regulations, but they work differently.
A shortfill is a nicotine-free e-liquid sold in a bottle that isn't completely filled — leaving room for you to add a nicotine shot. For example, a 50ml shortfill comes in a 60ml bottle, so you can add a 10ml nicotine shot to reach your desired strength.
A longfill takes a different approach. The bottle contains a concentrated flavour base — usually 10–20ml in a 60ml bottle — and you top it up with a nicotine base or plain base liquid to fill the rest.
The main difference is the ratio: shortfills are nearly complete and need a small nicotine boost, while longfills require more base liquid to dilute the flavour concentrate.
Both formats allow you to customise your nicotine strength and are popular among experienced vapers who prefer larger quantities of e-liquid at lower cost per ml.