What formula is used?
Wh = mAh × V ÷ 1000.
Battery capacity to energy
mAh to Wh Calculator
Convert battery capacity in milliamp-hours to nominal watt-hours using battery voltage.
Interactive calculator
mAh to Wh Calculator
Result
18.500 Wh
Wh = mAh × V ÷ 1000
Live circuit diagram
mAh to Wh Calculator visualized in real time
Values update as you use the calculator.
Input
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Circuit setting
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Calculated output
Enter values to see the live result
Quick answers
mAh to Wh Calculator: quick answers
Get concise answers to the most common mah to wh calculator questions before reviewing the formulas, examples, and detailed guidance below.
Why is the second input needed?
Voltage is needed because amp-hours measure charge, not energy.
Can I use decimal values?
Yes, enter positive decimal values in the displayed units.
Formula
mAh to Wh formulas
Choose the formula that matches the electrical system and known values.
Energy
Wh = mAh × V ÷ 1000
Use nominal pack voltage.
Capacity
mAh = Wh × 1000 ÷ V
Inverse relationship.
Amp-hours
Ah = mAh ÷ 1000
Convert capacity units first.
How to use
Calculate in five clear steps
Check every unit and use measured or nameplate values where possible.
- 1. Enter capacity in mAh.
- 2. Enter nominal voltage.
- 3. Multiply capacity by voltage.
- 4. Divide by 1000.
- 5. Account for usable depth and losses separately.
Worked examples
Practical calculation examples
Examples make the formula and its assumptions easier to verify.
5,000 mAh at 3.7 V
18.5 Wh
10,000 mAh at 3.7 V
37 Wh
2,000 mAh at 12 V
24 Wh
1,000 mAh at 5 V
5 Wh
20,000 mAh at 3.85 V
77 Wh
100,000 mAh at 12 V
1,200 Wh
Accuracy
Common mistakes and limitations
The result is only as reliable as the selected formula and input data.
Conversion library
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Continue from the mAh to Wh Calculator to a dedicated conversion tool for watts, amps, volts, kW, kVA, energy, batteries, or circuit calculations. Each linked page includes its own formula, examples, and guidance.
FAQ
mAh to Wh questions
Direct answers to common calculation questions.
What formula is used?
Wh = mAh × V ÷ 1000.
Why is the second input needed?
Voltage is needed because amp-hours measure charge, not energy.
Can I use decimal values?
Yes, enter positive decimal values in the displayed units.
Why do units matter?
Incorrect prefixes or charge units can change a result by factors of 1000 or more.
Is this an exact conversion?
The arithmetic is exact for the stated ideal relationship and input assumptions.
Does battery efficiency matter?
Yes for real battery systems; nominal energy conversion does not include losses.
Can voltage change in a battery?
Yes. Battery voltage varies with chemistry, state of charge, load, and temperature.
Can this replace manufacturer data?
No. Use cell and pack specifications for final design.
Is electron-volt an SI unit?
It is a widely used non-SI energy unit accepted for atomic and particle physics.
Can I copy the result?
Yes, use the copy button.
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