mAh to Kilowatt-Hour Calculator
Convert milliampere-hours (mAh) to kilowatt-hours (kWh) instantly. Enter battery capacity and voltage to get Wh, kWh, and joules — with formula and common battery examples.
mAh to kWh Calculator
Convert battery capacity to energy units
Enter the battery capacity in milliampere-hours
Nominal voltage of the battery (see common values below)
Select a preset or enter a custom voltage above
Conversion Results
Battery energy analysis
Enter your battery capacity in mAh and the voltage, then click Convert to see the energy in watt-hours and kilowatt-hours.
mAh to kWh FAQ
Answers to the most common questions about converting battery capacity (mAh) to energy (kWh) and understanding the relationship between charge, voltage and energy.
To convert milliampere-hours (mAh) to kilowatt-hours (kWh), use the formula: kWh = (mAh × V) / 1,000,000, where V is the voltage in volts. First multiply the mAh value by the voltage to get milliwatt-hours (mWh), then divide by 1,000,000 to convert to kilowatt-hours. For example, a 5000mAh battery at 3.7V equals 0.0185 kWh.
A milliampere-hour (mAh) is a unit of electric charge commonly used to describe the capacity of small batteries such as those in smartphones, power banks, and laptops. It represents the amount of charge a battery can deliver over time — for example, a 3000mAh battery can theoretically supply 3000 milliamperes (3 amps) for one hour, or 1500mA for two hours.
A kilowatt-hour (kWh) is a unit of energy equal to one kilowatt (1,000 watts) of power sustained for one hour. It is the standard unit used by electricity companies for billing. One kWh equals 3.6 million joules. For context, a typical UK household uses about 8–10 kWh per day, and a 100W light bulb running for 10 hours consumes 1 kWh.
The voltage depends on the battery type: Lithium-ion/LiPo cells (phones, laptops, power banks) are typically 3.7V nominal (4.2V fully charged). Standard alkaline AA/AAA batteries are 1.5V. NiMH rechargeable cells are 1.2V. Car batteries are 12V. USB power banks output 5V but internally use 3.7V cells. Check the battery label or datasheet for the nominal voltage rating.
A 10000mAh power bank with standard 3.7V lithium cells contains approximately 0.037 kWh (37 Wh) of energy. However, due to conversion losses during charging (typically 15–25% efficiency loss), the usable energy delivered to a device is closer to 0.028–0.031 kWh. This is well below the 100Wh limit allowed in carry-on luggage on most airlines.
Watt-hours (Wh) and kilowatt-hours (kWh) measure the same thing — energy — but at different scales. 1 kWh = 1,000 Wh. Wh is commonly used for smaller batteries (laptops, power banks), while kWh is used for larger energy quantities like household electricity consumption and electric vehicle batteries. To convert: divide Wh by 1,000 to get kWh.
Yes. For lithium-ion and lithium-polymer batteries, use the nominal voltage of 3.7V (or 3.6V/3.8V depending on the specific chemistry). Enter the mAh capacity printed on the battery and 3.7V as the voltage. This calculator will give you the stored energy in both Wh and kWh. Note that the actual usable energy will be slightly lower due to conversion inefficiencies.
mAh measures electric charge, not energy. To get energy (Wh or kWh), you must multiply charge by voltage because Energy = Charge × Voltage. Two batteries with the same mAh but different voltages store different amounts of energy. For example, a 5000mAh battery at 3.7V stores 18.5Wh, while a 5000mAh battery at 12V stores 60Wh — over three times more energy despite the same charge capacity.