Qi charging lets you power your phone or tablet by placing it on a pad instead of plugging in a cable

Qi (pronounced "chee") is a wireless charging standard that transfers power through the air using electromagnetic fields. You place your device on a charging pad or mat, and power flows from the pad to a receiver coil built into your phone or tablet — no cable, no connector, no physical contact needed between the two.

The technology has been around since 2008, but it became common in phones only in the last five to ten years. Today, most newer iPhones, Samsung Galaxy phones, and many Android devices include Qi receivers built in. Some older phones and budget models do not have this feature, which is why you need to check whether your specific device supports it before buying a charging pad.

Qi charging is slower than wired charging — a typical Qi pad delivers 5 to 15 watts of power, while a cable can deliver 20 to 65 watts depending on the phone and charger. This means a full charge takes longer, usually 2 to 4 hours instead of 30 minutes to an hour. The tradeoff is convenience: you do not have to hunt for the right cable or worry about connector wear.

Key Takeaways

  • Qi charging works by placing your device on a pad that sends power wirelessly through electromagnetic fields, with no cable required.
  • Most iPhones from iPhone 8 onward and most Samsung Galaxy phones from Galaxy S6 onward have Qi receivers built in, but older and budget phones may not.
  • Qi charging is slower than wired charging — expect 2 to 4 hours for a full charge instead of under an hour with a cable.
  • Qi pads come in different wattages and designs, and a higher-wattage pad will charge your phone faster if your phone supports that wattage.
  • Metal phone cases and thick protective cases can block the wireless signal, so you may need to remove your case or buy a Qi-compatible case.

How to check if your phone or tablet has Qi built in

The fastest way is to check the manufacturer's specifications for your exact model. For iPhones, any model from iPhone 8 and newer supports Qi — that includes iPhone 8, 8 Plus, X, 11, 12, 13, 14, 15, and all their variants. For Samsung, Galaxy S6 and newer models support Qi, as do most Galaxy A and Galaxy M series phones made in the last five years.

If you own an Android phone from another manufacturer, search the model name plus "Qi charging" in a search engine. The official product page or the phone's manual will state whether it has wireless charging. If you cannot find a clear answer, assume it does not have Qi — manufacturers advertise this feature prominently because it is a selling point.

You can also test your phone physically. Place it on a Qi charging pad that is plugged in and turned on. If your phone begins charging (you will see a charging indicator on the screen or feel a slight vibration), it has Qi. If nothing happens after 10 seconds, your phone does not support it.

What to know about Qi charging pads and their wattage

Qi pads come in different power outputs, measured in watts. A 5-watt pad is the slowest and is often included free with some phones. A 10-watt pad is standard and charges most phones in 2 to 3 hours. A 15-watt pad is faster and is what you want if you charge overnight or need a quicker top-up. Some newer pads claim 20 watts or higher, but most phones cap out at 15 watts, so the extra power is wasted unless you own a very new flagship phone.

The pad itself does not determine speed alone — your phone has to support that wattage. An iPhone 8 or 11 will charge at 7.5 watts maximum, no matter what pad you use. An iPhone 12 or newer will charge at up to 15 watts. A Samsung Galaxy S21 or newer will charge at up to 15 watts. Check your phone's manual or the manufacturer's website to see what wattage it supports, then buy a pad that matches or exceeds that number.

Qi pads come in several physical styles: flat pads you set your phone on, stands that prop your phone at an angle, and car mounts. A flat pad is cheapest and takes up little space. A stand is useful if you want to watch video or check notifications while charging. All three work the same way electrically — the difference is just how you position your phone.

Why metal cases and thick protective cases can block Qi charging

Qi charging uses electromagnetic fields to transfer power, and metal is an excellent conductor that disrupts those fields. If your phone case contains metal — whether a metal frame, metal kickstand, or metal reinforcement — it can block the signal partially or completely. Thick cases made of rubber or plastic can also block the signal if they are more than 3 to 5 millimeters thick, because the coil inside your phone needs to be close to the pad.

The simplest solution is to remove your case before charging. If you do not want to do that every time, buy a case labeled "Qi-compatible" or "wireless charging compatible." These cases are made of non-conductive materials and are thin enough to let the signal through. They cost a few dollars more than a standard case but save you the hassle of removing and replacing your case each time you charge.

If you already own a case and want to test whether it blocks Qi, place your phone in the case on a Qi pad. If it charges normally, the case is compatible. If it charges very slowly or not at all, the case is blocking the signal and you will need to remove it or switch to a Qi-compatible case.

Qi charging versus wired charging: speed and battery health

Wired charging is faster — a typical phone charges from 0 to 50 percent in 20 to 30 minutes with a modern fast charger, while Qi charging takes 45 minutes to an hour for the same amount. Wired charging also generates more heat, which can stress your battery slightly over many years, though modern phones manage this with built-in temperature controls.

Qi charging is slower and generates less heat, which some people believe is gentler on battery health over time. The difference is small — a battery charged with Qi versus a cable will not show a noticeable difference in lifespan unless you charge thousands of times. What matters more for battery health is avoiding extreme temperatures, not letting your phone fully drain regularly, and not leaving it plugged in at 100 percent for days at a time.

For daily use, Qi charging is fine and convenient. For situations where you need a full charge quickly — before a trip, before a long day away from power — a wired charger is the better choice. Many people use both: Qi pads at home and work for everyday charging, and a wired charger in their bag or car for emergencies.

Multi-device Qi charging pads and their limitations

Some Qi pads can charge two or three devices at once — for example, a pad that charges your phone and your smartwatch simultaneously. These pads have multiple coils built in, one for each device. They are convenient if you own several Qi-compatible devices, but they have a tradeoff: the total power is split between devices, so each one charges more slowly than it would on a single-device pad.

If you place a phone and a smartwatch on a dual-device pad rated for 15 watts total, the phone might get 10 watts and the watch 5 watts, rather than the phone getting the full 15 watts on its own. This is usually not a problem for overnight charging, but if you need a quick charge during the day, a single-device pad is faster. Check the pad's specifications to see how power is distributed before buying.

Multi-device pads also require precise placement — your phone and watch have to sit in the right spots on the pad for both to charge. If you move your phone slightly, it might stop charging. Single-device pads are more forgiving because you have more room to place your phone and still hit the coil.

Frequently Asked Questions

Can I use any Qi pad with any Qi phone?

Yes, Qi is a universal standard, so any Qi-certified pad will work with any Qi phone. The only variables are speed (a higher-wattage pad will charge faster if your phone supports it) and physical fit (your phone needs to sit on the coil, so very large phones might not fit on very small pads).

Does Qi charging work through a phone case?

It depends on the case. Thin plastic or rubber cases usually work fine. Metal cases or very thick cases block the signal. If you are unsure, test your phone on a Qi pad while in the case — if it charges, the case is compatible.

Is Qi charging safe for my battery?

Yes, Qi charging is safe. It generates less heat than wired charging and modern phones have temperature controls to prevent overheating. Using Qi charging will not damage your battery or shorten its lifespan compared to wired charging.

Why is my phone charging slowly on a Qi pad?

The most common reasons are a thick or metal case blocking the signal, your phone not being centered on the coil, or the pad being underpowered for your phone. Try removing your case and centering your phone on the pad. If it still charges slowly, check whether your phone supports the pad's wattage — some older phones cap out at 5 watts.

Can I charge my phone and smartwatch on the same Qi pad at the same time?

Only if the pad is designed for multiple devices. Standard single-device pads will charge whichever device is on top or closest to the coil. Dual-device pads have multiple coils and can charge both, but each device will charge more slowly than on a single-device pad.