We recommend power banks with a CHOICE Expert Rating of 75% or more.

This overall score is made up of performance (70%), ease of use (15%) and display (15%). Note: Discontinued models were tested using a different methodology. As such, these test results should be used as a general guide.

Each power bank is connected to an electronic load reference instrument, which is set to draw the maximum supported current from the fastest charging USB-A port. The voltage is determined by the power bank itself and recorded in the output, and data is graphed to show capacity drain over time. This gives us the total milliamp hours that the battery supports.

Based on port labelling (are inputs like USB-A, USB-C and fast charge clearly labelled?) and quality of instruction manual.

This score takes into account the position of the display on the unit and how easy it is to view and understand at a glance.

This refers to the power bank's ability to charge multiple devices at once, if more than one port is available. Higher scoring models showed a limited drop in charging performance when two or more devices were plugged in. This does not contribute to the overall score. In 2022 this method was altered to be a general performance test observed over the course of 30 minutes.

This is a broad guide based on our experience handling the devices.

We drain a power bank to the point where it won't charge a smartphone, then record how long it takes to recharge. Older models were charged using a low-end, one amp USB wall socket. Recent models were assessed with a two amp or 30-watt charger. Speeds will increase if you use a USB to wall-socket converter with a higher amperage.

For USB-A power banks, we use a a Maynuo M9712 DC electronic load reference instrument to work out the total milliamp hours that the battery supports. For USB-C power banks, we calculate what 80% of the battery capacity of our test phone is, then we use the power bank to charge the test phone to 80%, multiple times, until the power bank is fully discharged. We multiply the number of charges (including partial charges) by the 80% phone battery capacity value to give the usable capacity of the power bank. See our article on 'How we test power banks' for more information.

The output that can be reached from the power bank's fastest port.

The output that can be reached from the power bank's slowest charging port.

The maximum power output that can be achieved by the power bank when two devices are being charged simultaneously. 'N/A' ('Not applicable') is given to power banks with only one USB output.

A safety feature that deactivates the power bank if it begins to overcharge to prevent damage, fire or an explosion. Overcharge point measured in amperes.

A safety feature that activates protections/deactivates the power bank if it detects a short circuit.

The 'Multiple device' test method was altered in 2022. Though this doesn't contribute to the overall score, it does mean this aspect of the test is not directly comparable to models tested prior to 2022.

'Tested model' refers to power banks that are currently available in shops and online. 'Discontinued model' refers to power banks that are no longer available in shops, but may be available in second-hand stores. Note: Discontinued models were tested using a different methodology. As such, these test results should be used as a general guide (if you want a power that's no longer for sale).

Recommended retail price at the time of testing.

Most of the latest smartphones have a battery with around 3000mAh, so a 10,000mAh power bank should be able to charge the smartphone up to three times and a 20,000mAh power bank more than six times. Stated capacity is the capacity given by the vendor in milliamp hours (mAh).

The technology of the battery that's used. 'Not stated' means the vendor hasn't made it clear which technology is used.

The weight of the power bank in grams, without any cables or packaging.

Measured to the nearest millimetre.

Whether or not the power bank supports quick charging technology in any of its ports.

Lets you charge your smartphone by placing it on the power bank, rather than plugging it in. Your smartphone must also support wireless charging for this to work.

This refers to the type of display present on the power bank a Digital display is best, showing remaining charge in a percentage.

While additional ports are handy, it doesn't guarantee that the powerbank actually can charge multiple devices at the same time at full capacity.

A Nintendo Switch requires at least 18W from the powerbank to not only power the device but also charge the battery.

The ability of the power bank to stop charging once it's reached capacity. 'Not stated' means the vendor hasn't made it clear this protection is in place.