Wireless charging works by using electromagnetic fields to transfer power without a cable

Wireless charging sends electricity through the air between two coils — one in your charger and one in your phone — instead of through a plug. When you place your phone on a wireless charger, the coils line up and energy flows from the charger pad into your phone's battery. It is slower than plugged-in charging, usually adding 20 to 30 percent battery per hour instead of 50 to 80 percent, but you do not have to plug anything in.

Not every phone supports wireless charging. iPhones from the iPhone 8 onward have it built in. Most newer Android phones do too, but budget models and some older phones do not. The easiest way to check: look in your phone's settings under Battery or About Phone. If wireless charging is listed, your phone has the hardware. If you are not sure, your phone's manual or the manufacturer's website will confirm.

Key Takeaways

  • Wireless charging only works if your phone has a built-in receiver coil, which most phones made in the last five years have but some budget models do not.
  • You need a wireless charger pad or stand that plugs into power, and your phone must sit flat or at a slight angle on top of it to charge.
  • Wireless charging is about 30 to 50 percent slower than cable charging, so it works best overnight or when you are at a desk for a while.
  • Metal phone cases, thick cases, and some screen protectors can block the signal, so you may need to remove your case or buy a thinner one.
  • Wireless chargers come in different power levels — 5W, 10W, 15W, and higher — and your phone will only charge at the speed it supports, so a more expensive charger does not always charge faster.

What type of wireless charger to buy

Wireless chargers come in three main shapes: flat pads, stands, and car mounts. Flat pads are cheapest and take up little space, but you have to lay your phone down flat to use it. Stands let you prop your phone up at an angle so you can see the screen while it charges, which is useful if you want to watch videos or check notifications. Car mounts clamp to your dashboard or air vent and charge while you drive, though these are less common and more expensive.

The power level matters less than you might think. Chargers are sold as 5W, 10W, 15W, or higher, but your phone only charges at the speed it supports. An iPhone 8 through iPhone 12 charges at 7.5W maximum, so buying a 15W charger will not make it faster — it will just cost more. iPhone 13 and newer support up to 15W. Most Android phones support 10W to 15W, though some flagship models support 20W or higher. Check your phone's manual to see what it actually accepts, then buy a charger that matches or exceeds that number.

Brands matter less for basic wireless chargers than they do for cables. Any charger that meets the Qi standard (the universal wireless charging format) will work with any Qi-compatible phone. Anker, Belkin, and Samsung make reliable chargers in the $15 to $40 range. Avoid chargers with no brand name or suspiciously low prices, as they may overheat or charge slowly.

How to set up and use a wireless charger

Plug the charger into a power outlet using the cable that comes with it. Place your phone in the center of the pad or stand, screen-side up. Most chargers have a light that turns on when your phone is charging — usually green or blue. If the light does not come on, move your phone slightly; the coils have to align properly. You should feel no heat from the charger or phone during normal use. If either gets hot to the touch, unplug it and try a different charger.

Wireless charging works through most phone cases, but thickness matters. Cases thinner than 3 millimeters usually work fine. Thicker cases, especially those with metal reinforcement or card slots, can block the signal. If your phone is not charging, try removing the case. If it charges without the case but not with it, you need a thinner case or a charger with higher power output.

Metal phone cases, metal screen protectors, and some metal-rimmed cases will not work with wireless charging at all — the metal blocks the electromagnetic field. If your phone has a metal case, you will need to remove it to charge wirelessly, or switch to a cable charger instead.

Why wireless charging is slower than cable charging

Wireless charging transfers power less efficiently than a cable does. Some energy is lost as heat during the transfer, so a 15W wireless charger does not deliver the same speed as a 15W cable charger. This is why wireless charging typically adds 20 to 30 percent battery per hour, while a cable charger can add 50 to 80 percent in the same time.

Wireless charging is best used when you have time — overnight, at your desk during work, or in a car during a long drive. If you need your phone charged quickly, a cable charger will always be faster. Some phones support "fast wireless charging" at 15W or higher, which is quicker than standard wireless charging but still slower than a good cable charger.

Common problems and how to fix them

Phone not charging: Check that the charger is plugged in and the light is on. Move your phone to the center of the pad. Remove your case if it is thick. Make sure there is no metal object between your phone and the charger. If none of that works, try a different charger to rule out a broken pad.

Charging very slowly: Your case may be too thick. Remove it and try again. The charger may be underpowered for your phone — check your phone's manual and buy a charger that matches its supported wattage. Wireless chargers also slow down if your phone gets warm, so make sure the room is cool and the charger has air around it.

Phone getting hot: Unplug the charger when ready. Wireless chargers should be warm to the touch but not hot. If your phone is hot, the charger may be faulty or the coils may be misaligned. Try a different charger. If your phone gets hot with every wireless charger, the receiver coil in your phone may be damaged and you should use cable charging instead.

Charger light not turning on: Make sure the outlet works by plugging in another device. Check that the cable is fully inserted into both the charger and the outlet. If the light still does not come on, the charger is broken and needs to be replaced.

When to use wireless charging versus cable charging

Use wireless charging when you have 30 minutes or more and do not need your phone urgently. It is ideal for overnight charging, desk work, or keeping your phone topped up during the day. Use a cable charger when you need your phone charged in under 30 minutes or when you are on the go. Cable charging is also your only option if your phone does not support wireless charging or if you have a metal case you do not want to remove.

Many people keep both: a wireless charger at home or the office for convenience, and a cable charger in their bag or car for speed. This way you get the benefit of wireless charging when you have time and can still charge quickly when you need to.

Frequently Asked Questions

Does wireless charging damage my phone battery?

No. Wireless charging uses the same battery technology as cable charging and does not harm the battery itself. However, all batteries degrade slightly with every charge cycle, whether wireless or wired. Wireless charging may cause slightly more heat, which can speed up battery aging if your phone gets hot during charging — so avoid using your phone while it charges wirelessly.

Can I use any wireless charger with my phone?

Any Qi-certified charger will work with any Qi-compatible phone. The power level (5W, 10W, 15W) does not have to match exactly — your phone will charge at whatever speed it supports, up to the charger's maximum. A 15W charger will work with a phone that only supports 7.5W, but it will not charge faster.

Will my phone charge through a thick case?

Most cases thinner than 3 millimeters will work. Thicker cases, especially those with metal or reinforced edges, may block the signal. Remove your case and try charging — if it works without the case, you need a thinner case or a higher-wattage charger. Metal cases will never work with wireless charging.

Is wireless charging safe?

Yes. Wireless chargers use low-power electromagnetic fields that are safe for daily use. They do not emit radiation in the way that cell towers do. The main safety concern is overheating — if your phone or charger gets hot, unplug it and use a different charger or switch to cable charging.

Why does my phone charge slower on a wireless charger than my friend's phone?

Different phones support different wireless charging speeds. An older iPhone may support only 7.5W while a newer Android phone supports 15W. Your charger may also be lower-wattage than theirs. Check your phone's manual to see its maximum supported speed, then buy a charger that matches it.