We’ve all been there - your phone is on 3%, the Uber hasn’t arrived, and your mate's directions include the words “second left after the dairy”. In these moments, a trusty power bank is the real MVP. But with so many options out there, how do you know what size or capacity to go for? Is bigger always better? And what do all those mAh numbers actually mean?
Let’s break it down, nice and easy, so you can find the right power bank for your lifestyle - whether you're off-grid for the weekend or just want to survive a full workday without your phone dying at 2 pm.
Wait, what’s mAh again?
mAh stands for milliamp hours. In human terms, it’s a measure of how much juice a power bank can hold. The higher the number, the more charge it can store - and the more times it can top up your devices. Think of it like a fuel tank: a small car might only need a few litres to get around town, but a boat with twin outboards? That thing would probably be safer with a bit more.
So, before picking a power bank, figure out what you'll be charging and how often. Are you just keeping your phone alive, or are you packing a tablet, wireless earbuds, smartwatch, and maybe even a USB-C laptop?
Typically, the bigger the capacity, the bigger the power bank, so while you may think going for the most capacity you can get is best, if your needs are much less, you may be better off going with something a little smaller and more portable. No one wants to lug a big tank around every day!
Before we get started, here are some quick and helpful tips on other things to consider, because size isn’t everything!
If you’re looking for a more in-depth guide on this, head over to our Top Power Banks and Portable Chargers article. Here’s a quick recap:
- Number/Type of ports – this is super important if you’re charging multiple devices. You also don’t want a power bank that doesn’t have the exact port you need for your device.
- Charging speed – especially with modern devices, it’s important to have a power bank that supports fast charging, or you could be waiting an eternity!
- Travel restrictions – if you travel a lot, you’ll already know how essential a power bank can be. If you want to make sure your power bank is suitable for travel, check out our helpful article on travelling with power banks.
- Wireless capabilities – another consideration with modern technology is the ability to charge wirelessly. If you have devices that can be charged wirelessly, consider looking for power banks that support wireless charging.
- Pass through charging – look for this if you want to charge your phone and the power bank at the same time. Handy on a nightstand.
For the Minimalist: 5,000 - 10,000mAh
If you're not charging a variety of devices, and your phone makes it through the day easily, a power bank of this size may be best for you. These are lightweight, fit in your pocket or handbag, and are great for daily top-ups. Perfect for students, commuters, or anyone who spends more time near power outlets than in the wilderness.
To put it into perspective:
The Samsung Galaxy S25 Ultra, Samsung’s latest flagship phone (tech talk for Samsung’s crème of the crop), has a 5,000mAh battery capacity. This means that a 5,000mAh power bank can usually give it a little less than a full charge. This is due to a small amount of efficiency loss which occurs during charging.
A 10,000mAh one? Based on the above, a 10,000mAh power bank will get you almost 2 full charges on your Samsung Galaxy S25 Ultra.
It’s also important to consider that if you have a power bank handy, you typically won’t let your phone battery die completely. So if you plug in once your battery life is around 20%, for example, then it’s safe to say you can pretty much get your Galaxy S25 Ultra up to 100% approximately 2 times.
The AirPods Pro 2 have a battery capacity of just over 500mAh, so with a 5000mAh power bank, you could get just under 10 charges, should you ever need that much. Alternatively, you could get your phone up from a relatively low battery to full, and your AirPods from empty to 100% from one fully charged 5,000 mAh power bank. The possibilities are endless!
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For the All-Rounder: 10,000 - 20,000mAh
This range is the sweet spot for most people. It’s still pretty portable but gives you more headroom to charge a phone several times, or comfortably top up a second device like earbuds, a smartwatch, or even a small tablet.
If you’re someone who’s often out and about, forgets to charge their phone at night (no judgment), or travels regularly, this is probably your zone.
Bonus: Many in this range support fast charging and multiple USB ports, so you can share with a friend. Or not. Up to you.
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For the Power User: 20,000mAh and above
Alright, now we’re talking serious power. These are for the folks who carry more than one device, travel long distances, go camping, or just really hate the idea of running out of battery. We’re talking tablets, USB-C laptops, gaming handhelds - the works.
Some high-capacity power banks also support things like Power Delivery (PD) and Quick Charge (QC), meaning they can even top up your laptop or fast-charge your phone in record time. Ideal if you're the designated tech support friend or the kind of person who brings a power strip to the beach.
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So, what’s the right one for you?
If you just need a backup for your daily commute - something that’ll save your phone when it’s hanging on for dear life - a 10,000mAh bank is probably your best mate. But if you’re heading to a music festival, travelling, or lugging multiple devices around, a bigger 20,000mAh+ model will have your back.
Either way, there’s no wrong choice - just the one that fits your lifestyle. And once you’ve got the right one, you’ll wonder how you ever lived without it. Because in 2025, a flat phone battery is basically a crisis.
Not sure where to start? Check out our full range of power banks at PB Tech - from slim and sleek to heavy-duty bricks with enough power to resuscitate a laptop and a half.
Power up, stay charged, and never let low battery anxiety ruin your day again.
