mAh (milliamp-hours) tells you how much charge a power bank holds, but translating that to real-world device charges requires a bit of math.

The Efficiency Factor

Power banks don't deliver 100% of their rated capacity to your device. Voltage conversion and heat loss mean you typically get about 70% of the rated mAh as usable charge. A 10,000mAh power bank delivers roughly 7,000mAh to your phone.

Real-World Charging Estimates

  • 5,000mAh: About 1.2 full charges for an iPhone 15. Good for a single emergency top-up.
  • 10,000mAh: About 2.5 charges for a phone or 0.8 charges for a tablet. The sweet spot for daily carry.
  • 20,000mAh: About 5 phone charges or 1.5 tablet charges. Best for travel, camping, or multi-day trips.

Weight vs Capacity

Higher capacity means more weight. A 5,000mAh power bank weighs about 4 oz — barely noticeable in a pocket. A 20,000mAh bank weighs 12-15 oz, which is fine in a backpack but noticeable in a jacket pocket. Consider how you'll carry it before choosing capacity.

Fast Charging Support

Look for power banks with USB-C PD (Power Delivery) if you want to charge laptops or fast-charge phones. Our 20,000mAh power bank supports 30W PD output, enough to charge a MacBook Air at moderate speed.

For most people, 10,000mAh is the right balance — enough for a full day of heavy phone use, light enough to carry comfortably, and priced reasonably.