kWh to mAh Calculator: Kilowatt-Hours to Milliamp-Hours

To convert kWh to mAh, multiply the energy in kilowatt-hours by 1,000,000 and divide by the battery voltage: mAh = (kWh × 1,000,000) / V. A 1 kWh battery at 12 V holds about 83,333 mAh of charge.

That single division is where most confusion starts. A kilowatt-hour is a unit of energy, the total work a battery can do. A milliamp-hour is a unit of electric charge, how much current the battery can push for an hour. The two are not interchangeable on their own. Charge multiplied by voltage gives energy, so you can only move between them when you know the voltage the battery runs at.

People reach for this conversion when a product is rated in one unit but they think in the other. A home storage battery or an EV pack is sold in kWh. A phone, a power bank, or a drone cell is sold in mAh. Putting a 13.5 kWh wall battery into milliamp-hours produces a number in the millions, which is rarely how anyone would label such a pack, but the math is exact once the voltage is fixed.

How to Use the kWh to mAh Calculator

1. Enter the energy value in kilowatt-hours (kWh). This is the figure printed on the battery or power station spec sheet.
2. Select or type the battery nominal voltage. Use the pack voltage, not a single cell, unless you are working at cell level.
3. Read the result in milliamp-hours (mAh). At this scale the amp-hour (Ah) or watt-hour (Wh) value is usually more practical, so divide by 1,000 for Ah.
4. Change the voltage to see how the mAh figure moves. Higher voltage gives fewer mAh for the same energy.

kWh to mAh Formula and Step-by-Step Derivation

The formula comes from two simpler conversions chained together. First, kilowatt-hours become watt-hours by multiplying by 1,000. Then watt-hours become milliamp-hours by dividing by voltage and multiplying by 1,000. Combine the two factors of 1,000 and you get the single constant of 1,000,000.

Written as a chain: kWh × 1,000 = Wh, then (Wh / V) × 1,000 = mAh. Collapsed into one step, mAh = (kWh × 1,000,000) / V. The voltage sits in the denominator because charge equals energy divided by voltage.

To check a result or work backwards from a power bank rating, the inverse confirms the energy:

Worked Examples: kWh to mAh at Real Battery Voltages

Each example uses the voltage that actually applies to that class of battery. The same energy gives wildly different mAh figures depending on voltage, which is the whole point of the conversion.

Example 1, 5 V USB power bank (consumer): A 0.1 kWh power bank (100 Wh, the common airline-cabin limit) at 5 V holds (0.1 × 1,000,000) / 5 = 20,000 mAh. Most power banks print the 3.7 V cell rating instead, around 27,027 mAh, which is why a "27,000 mAh" bank and a "100 Wh" bank can be the same product.

Example 2, 12 V automotive and solar (North America): A 1.2 kWh lead-acid or LiFePO4 battery at 12 V gives (1.2 × 1,000,000) / 12 = 100,000 mAh, which is the same as a 100 Ah rating. The Ah figure is how this battery is normally sold; the mAh form just multiplies by 1,000.

Example 3, 51.2 V LiFePO4 rack (global solar storage): A 2.4 kWh server-rack battery at 51.2 V works out to (2.4 × 1,000,000) / 51.2 = 46,875 mAh, or 46.875 Ah. A 16-cell LiFePO4 string sits at 51.2 V nominal, common in off-grid and telecom backup from Europe to South Asia.

Example 4, 400 V EV pack (Europe): A 50 kWh electric-car battery at 400 V is (50 × 1,000,000) / 400 = 125,000 mAh, or 125 Ah.

kWh to mAh Conversion Chart for Common Values

This chart lists frequently searched kilowatt-hour values converted to milliamp-hours at three common voltages: 3.7 V (single lithium cell), 12 V (automotive and small solar), and 48 V (telecom and home storage). For any other voltage, use the calculator above.

Battery Voltage and Chemistry Set the kWh to mAh Result

Voltage is the one input that changes the answer, and voltage depends on chemistry and cell count. A 1 kWh battery is 270,270 mAh at 3.7 V but only 20,833 mAh at 48 V. Use the nominal voltage, not the fully charged or fully discharged voltage, because nominal is what manufacturers rate capacity against under IEC 61960.

The table below lists nominal voltages by chemistry. Multiply the cell figure by the number of series cells to get pack voltage.

Global Standards and Regional Practices for Battery Energy Ratings

Battery capacity declarations follow IEC 61960 for portable secondary cells, which defines how rated capacity and nominal voltage are measured. Safety and transport are governed by IEC 62133-2 for portable lithium cells, IEC 62619 for industrial and stationary lithium systems, and UN 38.3 for shipping lithium batteries by air, sea, or road. Portable computing and cellular packs also reference IEEE 1625 and IEEE 1725.

The airline rule is where kWh, Wh, and mAh collide in practice. IATA limits passengers to lithium batteries up to 100 Wh in carry-on without approval, 100-160 Wh with airline approval, and forbids anything above 160 Wh in the cabin. Because 100 Wh is 0.1 kWh, the cabin limit is about 27,027 mAh at 3.7 V. A power bank advertised at 30,000 mAh is already over the no-approval threshold at that voltage, which catches many travelers out.

Stationary storage at kWh scale is installed under regional wiring rules: NEC Article 706 covers energy storage systems in the United States; Canada follows CSA C22.1, while the United Kingdom uses BS 7671, Australia and New Zealand use AS/NZS 5139, Germany applies VDE 0100, and India follows IS 732. Mains voltage differs by region, but the battery DC voltage in this conversion is set by the pack, not the grid.

Industry Applications of the kWh to mAh Conversion

The conversion shows up wherever a large battery rated in kWh meets a habit of thinking in mAh.

• Portable power stations: a 1 kWh unit at 12 V is 83,333 mAh, useful when comparing it against the mAh ratings of the devices it will charge.
• EV and e-mobility packs: traction batteries are rated in kWh, but cell-level work and BMS data are in mAh and Ah.
• Home and grid storage: residential and grid batteries are specified and installed in kWh, not mAh.
• Consumer electronics sourcing: matching a power bank's mAh to the Wh or kWh limit printed for shipping and air travel.
• Drone and UAV fleets: pack energy is planned in Wh and kWh, while individual cells are specified in mAh.

Common Mistakes and Safety Notes for kWh to mAh

The errors below account for most wrong answers and a few unsafe assumptions.

• Leaving out the voltage. Without a voltage, kWh and mAh cannot be linked at all. A bare "1 kWh to mAh" has no single answer.
• Mixing cell and pack voltage. Using 3.7 V for a pack that actually runs at 48 V inflates the mAh figure by 13 times.
• Treating mAh as energy. Two batteries with the same mAh hold different energy if their voltages differ. mAh is charge, not energy.
• Using mAh for kWh-scale batteries in real specs. At this scale, Ah or kWh is the sensible unit; the mAh number runs into the millions and invites typos.
• Ignoring the airline Wh limit. Convert your power bank back to Wh before flying, since the 100 Wh cabin rule is enforced in Wh, not mAh.

For energy storage and EV work, treat the result as a nominal figure. Usable capacity is lower than rated capacity once depth of discharge, temperature, and the Peukert effect are accounted for. Always size systems against the manufacturer's usable rating and the relevant code.

Cross-links: For amp-hours instead of milliamp-hours, use the kWh to Ah calculator. For watt-hour scale batteries, use the Wh to mAh calculator. To go the other way, use the mAh to kWh calculator, and for amp-hour energy work see the Ah to kWh calculator.

Professional disclaimer: This calculator provides nominal conversions for reference. Always verify capacity figures against the manufacturer's datasheet and local electrical codes, and consult a licensed electrician or qualified battery engineer for installation, sizing, or safety-critical work.