Why The mAh Number For Portable Battery Packs Matters (And What It Means)

Smaller battery packs and portable chargers are often labeled by capacity in milliampere-hours (mAh). That unit of measurement helps you gauge how much energy is stored in the batteries. If you understand the numbers, you can also figure out how many times a portable charger can charge devices like your phone, computer, or tablet. The higher the mAh rating, the more energy is stored, which means longer battery life for the power packs and more charges for your gear.

Power packs come in a wide range of capacities, from 2,500 mAh up to 50,000 mAh or more. Some of the best portable chargers chosen by Consumer Reports are between 5,000 mAh and 30,000 mAh. Smartphones, tablets, and laptops also have dedicated batteries, and if you review their specifications, you'll find the battery size listed in mAh. The Samsung Galaxy S26, for instance, has a 4,300 mAh battery, while the Google Pixel 10 has a 4,970 mAh battery.

A 5,000 mAh battery pack would charge both of those devices at least once. A 10,000 mAh battery pack would charge them twice, a 20,000 mAh portable charger would charge them about four times, and so on. When you're shopping for portable power packs, you can see how much energy they have per charge, allowing you to better assess how many times you could charge your phone or other devices. Bear in mind, laptops generally have much larger batteries, around 5,000 to 10,000 mAh, so most smaller packs would not be able to charge them fully.

Choose a power bank based on which devices you'll be charging and how many times you think you'll need to recharge them. A bigger battery will enable you to charge your phone, a tablet, a handheld console, and more, all from a single power bank. The mAh rating also clues you into potential restrictions. The FAA and TSA don't allow batteries exceeding 100 watt-hours (Wh), which is about 27,000 mAh, give or take, depending on the voltage. If you're choosing a portable charger to bring with you on flights, you'll want to choose TSA-approved power banks to make sure they're not confiscated at checkpoints.

If you're using the power bank to charge other gadgets, like a handheld gaming console, you'll want one with a big enough capacity to make it worthwhile. You can double your Nintendo Switch 2's battery life with the right portable charger. The same is true for a Steam Deck. The OLED model has a 6,470 mAh battery, while the older LCD model has a 5,200 mAh battery, so you'd want a power bank with at least 10,000 mAh, ideally higher than that.

There are other considerations when choosing a power bank, like how portable you want the unit to be. Larger options are referred to as portable power stations and have a big enough battery to charge devices dozens of times, if not more. Some can even power appliances during an outage. But they're bulky and not something you would bring on a plane — you could stow them in a van, RV, or camper, though. Their capacities are so large they're labeled in watt-hours, a bigger unit of measurement.