How to choose a power bank

Capacity and speed answer different questions

Capacity tells you how much charge the internal battery stores, commonly shown in mAh. Output in watts tells you about the charging power available. A higher-capacity power bank does not automatically charge a phone faster.

Do not divide the mAh numbers to promise full charges

The printed capacity usually describes the internal cells. Voltage conversion and charging losses reduce what reaches your phone. Using the phone while it charges also affects the result, so a 10,000 mAh power bank is not a guarantee of two full charges for a 5,000 mAh phone.

Watt-hours (Wh) express energy. Where the manufacturer supplies both voltage and capacity, Wh = (mAh ÷ 1,000) × voltage. Compare the manufacturer’s stated usable or rated output and tested charging examples for the exact model rather than making a fixed promise from cell capacity alone.

Check input, output and shared power

Match the connectors and charging protocol to your device. Check each port’s output and whether the power is shared when you charge more than one device. The input rating matters too: it affects how quickly you can recharge the power bank with a compatible charger and cable.

Choose for how you will carry it

Balance capacity against weight and size. For wireless or magnetic charging, check the supported phone models, charging standard and required case. Magnetic attachment does not prove charging compatibility.

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Manufacturer references

Anker: choosing a power bank