Capacity, Speed, and Size: What Actually Matters

Don't fall into the trap of thinking a 3,000mAh power bank will give your 3,000mAh battery smartphone a full charge. No portable charger runs at 100% efficiency. In truth, most average between 60 to 70%, with the best-performing models able to reach 80 to 90%. Tech Advisor As a rule of thumb, 5,000mAh handles a single phone charge, 10,000mAh hits the sweet spot between capacity and portability, and you want closer to 20,000mAh for laptops or multi-day trips.

Charging speed matters too. Look for USB-C Power Delivery (PD) support with at least 20W output for fast phone charging. If you need to charge a laptop, aim for 45W or higher. Some portable power banks include extra features like MagSafe compatibility, a built-in wall plug, or even a kickstand. Engadget Built-in cables are increasingly common and eliminate the "forgot my cable" problem entirely.

Our Top Picks

Anker Nano Power Bank 10K (around $40 to $50) Our best overall portable charger basically takes nearly everything good about budget picks and puts it in a better package. CNN The built-in USB-C cable folds away neatly, while a clever loop design lets you hold and use your phone while charging. The Anker Nano power bank is impressive for how much charge it delivers in such a small package, easily fitting in a jacket pocket. Engadget A screen shows exact battery percentage rather than vague LED dots.

INIU Portable Charger (around $20 to $25) This power bank thrive in phone recharging for the same price as a month of Netflix. CNN At 10,000mAh with 22.5W output, it handles most phones with ease. The compact size and budget price make it perfect for everyday carry or as a backup you keep in your bag permanently.

Anker 737 PowerCore 24K (around $110 to $130) The Anker 737 brings desktop-class charging to travel with a 24,000mAh battery and an impressive 140W output that can rapidly top up high-end laptops and multiple devices. Listful Three ports (two USB-C, one USB-A) let you charge everything at once. It's bulkier than pocket chargers, but essential for power users and laptop owners.

Belkin BoostCharge 20K with Integrated Cable (around $50 to $60) The Belkin Boost Charge 20K with Integrated Cable is one of the more affordable examples with built-in cables. It charged a Samsung Galaxy S24 Ultra from near-dead to full in an hour and 15 minutes. Engadget The magnetized cable tucks away when not in use, and you can still charge three devices simultaneously via the additional ports.

The Bottom Line

Match capacity to your needs: 10,000mAh for day trips, 20,000mAh+ for extended travel or laptop charging. Built-in cables and fast charging are worth paying slightly more for. And remember, TSA limits power banks to carry-on luggage only, with a 27,000mAh maximum at some airports.