How to choose a power bank with the right capacity for your iPhone

Suppose you have a power bank with a 10,000 mAh capacity and your phone has a 5,000 mAh capacity. You'd expect to be able to charge your phone about twice, but that's not entirely true. Every power bank has a certain efficiency and loses some capacity when charging another device. Most power banks have an efficiency of around 80-85%. This means the actual mAh capacity of a 10,000 mAh power bank is actually 8,000/8,500 mAh. Pay close attention to this when purchasing a power bank.

Here's how to calculate how many times you can charge an iPhone with a 5,000 mAh battery using a power bank with an 80% efficiency:

8,000mAh / 5,000mAh = 1.6 times

Suppose you have a power bank with a capacity of 20,000 mAh, then you can charge your phone 3.2 times, because:

(20,000 * 0.8) / 5000 mAh = 3.2 times charging.

Below you'll find an overview per iPhone model with the battery capacity and the number of times you can charge the model with a 10,000 and 20,000 mAh power bank.