Dell 4.5mm vs 7.4mm barrel charger — which do I need?
Dell laptops use two different round barrel sizes. Get the wrong one and it won't fit (or won't be recognised). Here's how to tell 4.5mm from 7.4mm.
Two sizes, not interchangeable
Newer slim Dell laptops use a 4.5mm × 3.0mm barrel; older/larger models use a 7.4mm × 5.0mm barrel. A 7.4mm plug won't fit a 4.5mm jack and vice-versa.
How to measure
Measure the outer diameter of your old charger's pin, or compare it to the size printed on the adapter. If unsure, photograph the tip and we'll identify it.