Why It Matters Which Charger You Use for Your Phone

There are always going to be situations where you need to charge up your phone but you don't have the bundled charger on hand—and Apple isn't bundling a charging block at all with the new iPhone 12 (though you still get a Lightning cable in the box).

So can you just plug any charger into your phone to juice it up, especially now that the vast majority of handsets support the same wireless charging and USB-C standards? The short answer is yes, but the long answer involves a bit more explanation.

Ranking Chargers

The most common spec you'll see on a charger is the watts (W)—essentially how much energy the charger can push toward your phone at once. Tablets and laptops will typically have chargers with a higher W value, as they have bigger batteries to fill (don't be surprised if your phone charger won't work with your laptop).

How quickly your phone goes from zero to a hundred in terms of battery life depends on both the watts coming from the charger and the maximum number of watts your phone can take (which you should be able to find out with a quick web search). The new iPhone 12, for example, can handle up to 20 W.

So if you buy the official 20-W charger from Apple, it's going to juice up your iPhone 12 about four times faster than the official 5-W charger from Apple. (Note too that the 20-W model supports the bigger iPad tablets, whereas the 5-W model doesn't, for the reasons we've already explained.)

This applies to laptop ports as well—the latest MacBook Pros can output 10 watts of power from their Thunderbolt/USB-C ports, which means they beat 5-W chargers but can't compete with the 20-W models. That's assuming your phone can take up to 20 W, by the way. If it tops out at 10 W, the MacBook Pro and the 20-W charger will restore its battery level at the same rate.

The OnePlus 8T supports 65W fast charging to fill a battery from zero in around 30 minutes.

Photograph: OnePlus

If you want the fastest battery charge possible for your phone, you need the charger that supplies as many watts as your phone can handle at once. Most of the time—but not always—the charger that came bundled with your phone will fit the bill.

When it comes to "fast charging," this is a technology that different manufacturers adopt in different ways, and the standards usually don't cross over between brands. The latest OnePlus 8T, for example, supports 65-W fast charging—it basically splits the battery up into two internally and charges both halves simultaneously.