🔋 Battery Capacity (mAh) Comparison – How to Know What You Really Need

Published: 16/09/2025

In today’s world, everything runs on batteries — phones, tablets, smartwatches, wireless earbuds, and even power banks. When buying a new device, one of the key things people look at is the battery capacity, usually written as mAh. But what exactly does mAh mean? And how do you compare devices based on it?

Table of Content

What is mAh?
How mAh Affects Battery Life
Battery Capacity Comparison Table
Common Myths About mAh
How to Choose the Right Battery Capacity
Conclusion

Let’s break it down in simple terms so you can understand what battery capacity really means — and how to choose the right one for your needs.

What is mAh?

mAh stands for milliampere-hour. It’s a unit that shows how much electric charge a battery can store. In even simpler words:

Higher mAh = Bigger battery = Longer potential usage time

But remember — this is only half the story. The actual battery life also depends on how much power the device uses. A phone with a 4000mAh battery might last longer than a 5000mAh phone if it uses less energy.

How mAh Affects Battery Life

Let’s say your device uses 500 milliamps per hour, and the battery is 5000mAh.
Here’s the formula:

Battery Life (in hours) = Battery Capacity (mAh) ÷ Device Usage (mA)

So:

5000 mAh ÷ 500 mA = 10 hours

But if the device uses more power (like 1000 mA), it will only last 5 hours.

That’s why mAh gives you a general idea, but not the full picture.

Battery Capacity Comparison Table

Here’s a simple table to compare common devices and their average battery capacities:

Device Type	Example	Battery Capacity (mAh)	Average Usage Time
Smartphone	Samsung Galaxy S23	3,900 mAh	20–24 hours
iPhone	iPhone 14	3,279 mAh	18–20 hours
Tablet	iPad Pro 11″	7,538 mAh	10–12 hours
Smartwatch	Apple Watch Series 8	308 mAh	~18 hours
Wireless Earbuds	AirPods Pro (case included)	~519 mAh	~24 hours (with case)
Power Bank	Anker PowerCore 20K	20,000 mAh	Charges a phone 4–5 times

Common Myths About mAh

🔸 Myth 1: Higher mAh means longer battery life
Not always. Battery life also depends on screen size, processor efficiency, and how the device is used.

🔸 Myth 2: All 5000mAh batteries are the same
No. Quality, brand, and technology matter too. A high-quality 4000mAh battery can outperform a cheap 5000mAh one.

🔸 Myth 3: mAh tells you charging speed
Wrong. mAh is about capacity, not how fast a battery charges. Charging speed depends on the charger (in watts) and charging technology (like fast charging, USB-C, etc.).

How to Convert mAh to Other Units

Ah (Ampere-hour):
1000mAh=1Ah1000 mAh = 1 Ah1000mAh=1Ah
Wh (Watt-hour):
Wh=(mAh×Voltage)÷1000Wh = (mAh × Voltage) ÷ 1000Wh=(mAh×Voltage)÷1000
Example: A 5000mAh battery at 3.7V = (5000 × 3.7) ÷ 1000 = 18.5Wh
kWh: Used for large batteries (like electric cars). 1 kWh = 1000 Wh

How to Choose the Right Battery Capacity

Here’s a quick guide based on your needs:

Use Case	Recommended Capacity (mAh)
Light phone usage	3000–4000 mAh
Heavy phone use / gaming	4500–6000 mAh
Travel / Camping	10,000–20,000 mAh (power bank)
Smartwatch	200–500 mAh
Wireless earbuds	300–600 mAh (with case)

Tip: Look for energy-efficient devices, not just bigger batteries.

Conclusion

Battery capacity, measured in mAh, is a simple yet powerful number that tells you how long your device might last. But don’t rely on mAh alone — also consider how much power your device uses, how efficient it is, and the quality of the battery.

Use this comparison guide as a tool to make smarter tech choices, whether you’re shopping for a new phone, a smartwatch, or a reliable power bank.

How long can a 5000mAh battery last?

It usually lasts between 10 to 24 hours on a smartphone, depending on usage.

What is a good battery capacity in mAh?

For smartphones, 4000 to 5000 mAh is considered good. For power banks, 10000 to 20000 mAh is ideal.

How many hours is a 4000 mAh battery good for?

It can last around 8 to 20 hours, depending on the device and how it’s used.

How long does a 10,000 mAh battery last?

As a power bank, it can charge a smartphone 2 to 3 times. In a device, it may last 20 to 40 hours depending on power consumption.