mAh to Wh Calculator Online – Easily convert mAh to Wh and Wh to mAh with our free calculator. Essential for checking power bank airline limits and battery capacity. Includes conversion formulas.
Battery Energy Calculator
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Understanding Battery Units: mAh vs. Wh
When shopping for power banks, laptop batteries, or smartphones, you will often see two different units used to describe battery capacity: mAh and Wh. While they are related, they measure different things. Our calculator above helps you convert between them effortlessly.
Definitions
What is mAh (Milliampere-hour)?
mAh stands for Milliampere-hour. It is a unit of electric charge. It represents the amount of electrical energy a battery can hold. Think of this as the size of the fuel tank in a car.
- Example: A 5000 mAh battery can output 5000 milliamps for 1 hour, or 1000 milliamps for 5 hours.
What is Wh (Watt-hour)?
Wh stands for Watt-hour. It is a unit of energy. Wh is often a more accurate measurement when comparing batteries of different voltages because it accounts for the power (Voltage) being used.
- Note: Airlines usually restrict power banks based on Wh (usually a limit of 100Wh), not mAh.
What is Voltage (V)?
Voltage is the “pressure” that pushes electricity through the device. To convert between mAh and Wh, you must know the voltage.
- Smartphones: Typically 3.7V or 3.8V.
- USB Standard: Typically 5V.
- Laptops: Vary between 11V to 15V+.
Conversion Formulas
If you want to do the math manually, here are the formulas used by our tool:
| Conversion | Formula |
|---|---|
| mAh to Wh | (mAh × V) ÷ 1000 = Wh |
| Wh to mAh | (Wh × 1000) ÷ V = mAh |
Real World Examples
Example 1: Smartphone Battery
You have a phone with a 4000 mAh battery rated at 3.7 Volts.
- Calculation:
(4000 × 3.7) / 1000 = 14.8 Wh
Example 2: Airline Power Bank Limit
Airlines limit batteries to 100 Wh. You have a 20,000 mAh power bank rated at 3.7 Volts. Is it safe to fly?
- Calculation:
(20,000 × 3.7) / 1000 = 74 Wh - Result: Yes, 74 Wh is less than the 100 Wh limit, so it is safe to bring on a plane.