How Many mAh Do I Need for a Phone? mAh Guide

How Many mAh Do I Need for a Phone? mAh Guide

Last Updated: September 30, 2026

How Many mAh for a Phone: Working Out Your Number

Key Takeaway Match the power bank to your phone's battery size first, then add a buffer for energy loss. A 10,000 mAh portable charger is the sensible starting point for most smartphones.

mAh, or milliampere-hour, describes how much charge a battery holds. Three things decide your real-world number: battery capacity, conversion loss, and weight.

How to Calculate Power Bank Charges (and Why Rated mAh Lies)

A 10,000 mAh power bank delivers roughly 6,000 to 7,000 mAh to your phone, not 10,000, because the step-up to USB output voltage burns 30 to 40 percent as heat.

Your Situation Phone Battery Recommended Power Bank Real Charges You Get
Light daily use 4,000 mAh 5,000 mAh About 0.8
Standard daily use 4,500 mAh 10,000 mAh About 1.4
Heavy user 5,000 mAh 20,000 mAh About 2.6
Watch Out Do not buy a power bank without checking its output wattage against your phone's fast charging standard. A high-capacity bank that only outputs at low wattage will charge a modern phone slowly, and you will blame the capacity when the real problem is power delivery.

Best Power Bank for Smartphones: Matching Capacity to Weight

The best power bank for smartphones is the smallest one that still covers your worst realistic day, because capacity and portability pull in opposite directions. A 20,000 mAh unit can weigh over 300g, fine in a backpack, miserable in a pocket.

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Comparison chart showing power bank capacity and weight next to a charging bracelet and a smartphone on a table
Comparison chart showing power bank capacity and weight next to a charging bracelet and a smartphone on a table
Pro Tip Keep a small top-up charger in your bag and a high-capacity bank at home or in your desk drawer. You get light daily carry plus full backup when you actually need it, without paying the weight penalty every single day.

A quick way to choose:

  • Commuter, light use: 5,000 mAh, under 150g
  • Most people: 10,000 mAh, around 200g
  • Heavy user or travel: 20,000 mAh, 300g and up

Getting the capacity right comes down to one habit: divide the rated figure by roughly 0.65, then divide again by your phone's battery size. Do that before you buy and you will stop overpaying for capacity you never receive. Phone and electronics accessories stocks portable chargers and everyday accessories with free shipping, free returns, a 30 day return policy, and secure payments protected by SSL encryption. Order now and carry a charger that actually matches how you use your phone.

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