Android devices have several charging technologies and techniques, from wireless charging to the fast charging protocols smartphone manufacturers offer. It can get complicated when determining what to look for in your next phone charger. The different wattage and amp numbers from specific Android device models add another level of confusion. Grabbing one of the best smartphone chargers will steer you in the right direction.

For example, one of the newest technologies for smartphone chargers is Gallium nitride (GaN). GaN chargers produce less heat, allowing higher charging speeds in a small form factor. A GaN charger will charge your phone quickly with fewer heat issues when compared to its silicon counterparts.

You'll want a reliable charger to charge your phone quickly and safely. Knowing how your charger is performing is just as crucial. We show you how in the guide below.

Download and use the Ampere app

Use an app for a cost-efficient, relatively speedy method to gauge your charging performance. We recommend the Android-friendly Ampere app for the quickest results.

  1. Download the Ampere app on your Android device. You'll find it on the Google Play Store. There's a pro version, but the free download is all you need.
  2. Look for the charging information for your phone to find its charging wattage or similar numbers. Specs pages or manuals should have this data. Google, for example, posts the minimum mAh for the Pixel 8 and recommends a 30W charger. Use these specs to make quick comparisons.
  3. Charge your device with the typical charger you use. Your battery should be depleted enough to actively charge for the most accurate measurements.
  4. Open the Ampere app, and let it run. You'll see Measuring at the top of the app. The bottom of the app detects and shows information about your device's battery, including its voltage, max capacity, and charge levels, which you may find helpful.
  5. Measured in mA (milliampere) at the top of the Ampere app, you'll see a minimum and maximum number with an average charge. Next, calculate the numbers: Watts = Volts X Amps. Round up your mA and voltage numbers to the nearest number, and convert mA to amps by dividing it by 1,000 (2900mA would become 3A). Find the wattage by multiplying them together.
  6. Compare wattage numbers with your Android charger and device specs to see if you're getting optimal performance. If your calculations show that your phone is charging at 10W, but you know it's rated for 15W fast charging, there's room for improvement.

Fast chargers may show around 3,000mA on today's devices. Slower chargers may show around 1,000mA, indicating that you can improve performance. Ampere also shows discharge times as you use your battery.

Alternative: Purchase a voltage meter

Plugable's USB-C voltage meter showing numbers.
Source: Plugable

Your primary alternative to using an app on your smartphone is to purchase a voltage meter or similar device. This lets you measure the electricity flowing into your Android device quickly and effectively. It's mechanically accurate and one of the best ways to diagnose a faulty or irregular charger. It's an expensive option, and you'll need some electrical math to analyze the results. If you're interested in such a method, here's what to try:

  1. Purchase a voltage meter. Affordable versions are available for testing consumer devices like phones. This USB-C meter from Plugable is one of the best options, currently available for around $25.
  2. The meter acts as an intermediary between your charging cable and your device. Plug it into your device, then plug your charging cable into the meter.
  3. The meter shows a running measurement of the electricity flowing into the device, including input voltage and mA/A values. To compare different chargers, convert these to wattage using the formula above or the amp values.

A physical device lets you switch between cables and chargers to see if any make an immediate difference. However, they come with limitations. The Plugable model mentioned, for example, does not support extended USB-PD power ranges of 28V or above.

Can changing chargers improve my Android charge speed?

It may help, but there are many factors at work. Switching to an upgraded charger may produce better results if your Android device supports a fast charging protocol. For example, say you have a phone that supports USB PD (Power Delivery) up to 25W of charging power. Your charger is limited and only supports up to 10W of charging. A new USB PD charger could lead to even faster charging results.

Changes like these depend on your Android device model, how new your phone is, and other details that can vary. Pay attention to the wattage and other specs when making comparisons. The charger your phone ships with often produces the best results. Other times, you can find an upgrade to use your phone's maximum charging capabilities beyond what you get from stock.

You're ready to test

Use these tools and methods to check the effectiveness of your Android device chargers. For example, to ensure you get what you paid for if you purchased a new charger for your smartphone. At the same time, you'll benefit from testing an older charger you've used for a while. You can also use the tips mentioned in this guide to diagnose problems with your device's battery.

You can check the battery-specific health stats of your smartphone to get a better idea of what kind of shape it's in. We walk you through the methods on Samsung devices, other Android phones, and iPhones.