How to compare charge rate per minute

Your laptop or phone is plugged in, but the battery seems to be climbing slowly while you work. You may be wondering whether the charger, cable, device, or your workload is responsible.

The Charger & Cable Test measures charging speed as battery percentage gained per minute. Use it to compare chargers or cables, but keep the test conditions consistent so you are comparing like with like.

Measure the charge rate

1. Open the Charger & Cable Test on the device you want to check. It appears only when the browser reports a battery, which can include laptops, tablets, and phones.
2. Connect the charger and cable you want to test. Wait until the device reports that it is charging, then note the battery percentage and whether the screen or demanding apps are in use.
3. Leave the device charging for about 10 to 15 minutes. Avoid changing the workload or connecting another charger during that interval.
4. Read the charge rate shown in percent per minute. Repeat the same check with another cable or charger, keeping the device, starting percentage, outlet, and workload as similar as possible.

If the tool does not appear or cannot read a battery, try a browser and device that report battery information. Browser support varies, and some phones do not expose battery data to web pages.

What the result means

The rate is steady and higher with one setup

If one charger and cable consistently add more percentage per minute under similar conditions, that combination is charging your device faster in that test. The result does not prove that the charger is delivering a particular number of watts. It measures battery percentage change, not electrical power directly.

The rate changes from one test to another

That can be normal. Charging speed changes with battery level, temperature, device activity, and the charging mode the device and charger agree to use. A short measurement can also be affected by a small change in the reported percentage. Repeat the test before deciding that a cable or charger is faulty.

The rate slows near a full battery

Many devices reduce charging speed as the battery gets close to full. This protects the battery and manages heat. A slower result at 85 percent is not a fair comparison with a test that began at 30 percent. Compare chargers at a similar starting percentage, preferably well below the level where your device usually slows charging.

The rate is zero or the battery percentage falls

The device may not be charging, or it may be using power faster than the charger supplies it. A laptop running a video call, for example, can use much of the incoming power. Check the charging indicator, try a lighter workload, and confirm that the charger is firmly connected.

How to improve or troubleshoot the rate

1. Check that the device says it is charging. A connected cable does not always mean power is reaching the battery. Look for the charging symbol or status in the device's own battery display.
2. Reduce the workload for a fair comparison. Close games, video exports, and other demanding tasks, or pause them during the measurement. Keep the screen brightness and connected accessories about the same for each run.
3. Try another outlet and reconnect the cable. Plug the charger directly into a wall outlet, then reconnect both ends of the cable. If the connection feels loose or charging starts and stops, test a different port if available.
4. Check the charger and cable ratings. A cable may transfer data but still be unsuitable for the charging speed your device supports. Compare the charger’s output rating with the device maker’s guidance, and use a cable rated for the required charging power.
5. Look for a charge limit or battery protection setting. On Windows 11, open Settings › System › Power & battery, then check whether your laptop maker provides a separate charging limit in its own utility or firmware settings. On a Mac, check System Settings › Battery › Battery Health for battery charging options. On Android, look under Settings › Battery for charging or battery protection options. On iPhone, check Settings › Battery › Charging on newer iOS versions, or Settings › Battery › Battery Health & Charging on older versions. Names and availability vary by device.
6. Let a hot device cool before testing again. Charging can slow when the battery or device is warm. Move it out of direct sun, stop demanding work briefly, and repeat the test after it cools. Do not put the device in a refrigerator or freezer.

When the charger, cable, or battery may be faulty

If the rate stays very low with a known-compatible charger and cable, test the charger with another compatible device if you can. If that device also charges slowly, the charger or cable may be the cause. If only one device has the problem, inspect its charging port for visible debris or damage, but do not scrape inside it with metal tools.

A cable that works only at a certain angle, a port that repeatedly disconnects, unusual heat, or a battery that swells needs attention beyond a browser test. Stop using damaged or swollen equipment and contact the manufacturer or a repair professional. A charge-rate reading alone cannot diagnose battery health or certify that a charger is electrically safe.

Read the number as a comparison, not a power rating

Percent per minute describes how quickly the displayed battery level rises during your test. For a rough hourly comparison, multiply the rate by 60. For example, 0.5 percentage points per minute is about 30 percentage points per hour at that observed rate. This is not a promise that the battery will keep charging at the same pace for an hour, and it is not a wattage measurement.

For a useful remote-work comparison, test each setup at a similar battery level and during a similar workload. A result is most helpful when it repeats, not when a single short run looks unusually fast or slow.