Charging Speed Test

This charging speed test measures how fast your phone's battery fills. It times each 1% step that your browser reports, works out the percent gained per minute, and from your battery size estimates the watts going into the battery. Save each result with a name to compare chargers and cables side by side, fastest first. It runs by itself in Chrome on Android phones and in Chrome or Edge on Windows, Mac and ChromeOS laptops. Safari, every iPhone browser and Firefox keep the battery level private, so on those the page gives you a simple manual timer instead.

How to test your phone's charging speed

1. Start with the battery between 20% and 50%. Charging is fastest there, so results from different chargers compare fairly.
2. Enter your battery size. Phone makers list it in mAh in the specifications, for example 5000 mAh. For a laptop, switch to Wh.
3. Plug in the charger and cable you want to test and press Start measuring.
4. Leave the phone alone with the screen on and the page open. Playing games or videos uses power and lowers the result.
5. Wait for at least three 1% steps. On a fast charger that takes about two minutes, on a slow one ten.
6. Type a name such as "20 W charger, white cable" and press Save. Then press New run, swap the charger or cable and repeat.

What the results mean

Time per 1% shows the seconds between level steps, and Time to 80% projects the current speed forward. The watts figure is an estimate of what reaches the battery, worked out from the battery size at a typical 3.85 volts. A worn battery holds less than its rated size, so the estimate reads a little high on an older phone.

Your phone charges slowly

Work through the causes from the most common:

• The cable. Worn, bent or very cheap cables are the top cause of slow charging. Try a different, short cable from a known brand and compare the two runs here.
• The charger's power. An old 5 W cube or a computer's USB-A port supplies only 2.5 to 5 W. Use a USB-C charger rated at 20 W or more.
• Charger and phone speak different standards. A charger has to support the phone's fast charging method. A Samsung phone on a charger without PPS gets about 15 W instead of Super Fast Charging, and many phones slow down on chargers built for another brand.
• Lint in the port. Pocket fluff packs into the bottom of the port and stops the plug seating fully. Switch the phone off and lift it out gently with a wooden toothpick.
• Heat. Phones slow charging when they are warm. Take off a thick case, keep the phone out of the sun and do not charge it on a bed.
• Using the phone. Games, navigation and a bright screen can take most of the power. Test with the phone idle.
• Wireless charging out of line. A phone a little off the center of a pad charges slowly or stops. MagSafe and Qi2 magnets line it up for you. A case with a metal plate for a car mount usually stops wireless charging, and it can block NFC too, which the nfc test shows.

If the phone barely charges at all with several cables and chargers, see the guide for a phone not charging when plugged in, which covers ports, software and battery faults.

Charging stops at 80% or slows near the end

This is normally on purpose. Charging slows past about 80% to protect the battery, and many phones can also stop at 80%:

• iPhone 15 and later: Settings, then Battery, then Charging, sets a limit between 80% and 100%. Older iPhones use Optimized Battery Charging, which waits at 80% and finishes just before you usually unplug.
• Samsung Galaxy: Settings, then Battery, then Battery protection. Maximum stops at 80%, or at a limit you choose up to 95% on One UI 7 and later.
• Google Pixel: Settings, then Battery, then Battery health, then Charging optimization, offers Adaptive Charging and, on the Pixel 6a and later, Limit to 80%.

To measure the real speed, test below 50% with these limits switched off.

Fast charging standards explained

• USB Power Delivery (PD) is the common USB-C standard used by iPhones, Pixels, Samsung phones, iPads and laptops. The charger and phone agree on a voltage of up to 20 V, and up to 48 V on the newest high power chargers. Most iPhones from the iPhone 8 on reach about 50% in around 30 minutes on a 20 W PD charger, and the iPhone 17, 17 Pro and 17 Pro Max do it in about 20 minutes on a 40 W one.
• PPS (Programmable Power Supply) is part of USB PD. It lets the phone ask for the voltage in small steps, which keeps the battery cooler. Samsung's Super Fast Charging and the fastest speeds on recent Pixels need a PPS charger.
• Quick Charge is Qualcomm's standard. Quick Charge 3.0 chargers top out around 18 W, and Quick Charge 4+ and 5 also work with USB PD.
• Brand standards such as OnePlus and Oppo SUPERVOOC or Xiaomi HyperCharge reach 65 W and more, but only with the brand's own charger and cable. With any other charger they fall back to a slower speed.
• Wireless pads deliver 5 to 15 W on most phones. The newest MagSafe and Qi2 chargers reach up to 25 W on phones that support it.

Cable quality matters

Every USB-C to USB-C cable is rated for at least 3 amps, enough for 60 W. Cables rated for 5 amps, needed for 100 W and above, carry a small chip that tells the charger so. Phones rarely need more than 3 amps, so for a phone the main differences are wear and build quality. Cables with the old USB-A plug at the charger end cannot use USB Power Delivery, so most phones charge more slowly through them. Save a run for each cable you own with this charging speed test online and throw out the slow ones. Data transfer speed is a separate question, measured with the usb speed test.

Testing charging on an iPhone, iPad or Mac

Apple does not let web pages read the battery, so use the manual timer: note the percentage, press Start timer, and after 15 minutes or more enter the new percentage. Each reading can be off by up to 1%, so longer runs are more precise. On iOS 26 and later, Settings, then Battery, also shows how long the iPhone needs to reach 80% and 100%, and since iOS 18 a Slow Charger notice appears there and on the Lock Screen when a stronger charger would help. On a MacBook, open this page in Chrome to measure automatically. For a laptop running on its battery, the laptop battery test checks the battery itself.

What a browser charging test cannot measure

Browsers report the battery level in 1% steps and nothing about current or voltage. This test therefore measures what reaches the battery over time, not what the charger delivers, and it cannot see the power the phone itself uses while charging. A USB-C power meter plugged between charger and cable shows the real volts, amps and watts. Battery health and cycle count are also out of reach for web pages.

Charging speed questions