mAh to kWh Converter

Convert milliamp-hours to kilowatt-hours with voltage input

Electric Charge (mAh)

mAh

Voltage (V)

Quick Conversions (at 3.7V)

Conversion Formula

Converting milliamp-hours to kilowatt-hours requires knowledge of the battery voltage. The formula accounts for both charge capacity and electrical potential.

Energy (kWh) = Charge (mAh) × Voltage (V) ÷ 1,000,000

kWh = mAh × V ÷ 1,000,000

This conversion is critical for calculating battery energy storage in portable power stations, smartphones, tablets, electric vehicles, and renewable energy systems.

Conversion Examples

Example 1: Smartphone Battery

A smartphone battery rated at 4,000 mAh with 3.8V voltage:

Identify the values: 4,000 mAh and 3.8V
Apply the formula: kWh = 4,000 × 3.8 ÷ 1,000,000
Calculate: kWh = 15,200 ÷ 1,000,000
Result: 0.0152 kWh or 15.2 Wh

Example 2: Power Bank

A portable power bank rated at 20,000 mAh with 5V output:

Values given: 20,000 mAh and 5V
Formula application: kWh = 20,000 × 5 ÷ 1,000,000
Calculation: kWh = 100,000 ÷ 1,000,000
Final result: 0.1 kWh or 100 Wh

Example 3: Electric Vehicle Battery Pack

An EV battery module with 60,000 mAh capacity at 48V:

Given specifications: 60,000 mAh and 48V
Using the formula: kWh = 60,000 × 48 ÷ 1,000,000
Perform calculation: kWh = 2,880,000 ÷ 1,000,000
Answer: 2.88 kWh

mAh to kWh Conversion Table

At 3.7V (Typical Li-ion Battery)

Capacity (mAh)	Voltage (V)	Energy (kWh)	Energy (Wh)
1,000 mAh	3.7 V	0.0037 kWh	3.7 Wh
2,000 mAh	3.7 V	0.0074 kWh	7.4 Wh
3,000 mAh	3.7 V	0.0111 kWh	11.1 Wh
5,000 mAh	3.7 V	0.0185 kWh	18.5 Wh
10,000 mAh	3.7 V	0.037 kWh	37 Wh
20,000 mAh	3.7 V	0.074 kWh	74 Wh
30,000 mAh	3.7 V	0.111 kWh	111 Wh
50,000 mAh	3.7 V	0.185 kWh	185 Wh

At 5V (USB Power Banks)

Capacity (mAh)	Voltage (V)	Energy (kWh)	Energy (Wh)
5,000 mAh	5 V	0.025 kWh	25 Wh
10,000 mAh	5 V	0.05 kWh	50 Wh
15,000 mAh	5 V	0.075 kWh	75 Wh
20,000 mAh	5 V	0.1 kWh	100 Wh
25,000 mAh	5 V	0.125 kWh	125 Wh
30,000 mAh	5 V	0.15 kWh	150 Wh

At 12V (Automotive & Solar)

Capacity (mAh)	Voltage (V)	Energy (kWh)	Energy (Wh)
10,000 mAh	12 V	0.12 kWh	120 Wh
20,000 mAh	12 V	0.24 kWh	240 Wh
50,000 mAh	12 V	0.6 kWh	600 Wh
100,000 mAh	12 V	1.2 kWh	1,200 Wh
200,000 mAh	12 V	2.4 kWh	2,400 Wh

Popular Battery Conversions

Smartphone Batteries

Modern smartphones typically range from 3,000-5,000 mAh at 3.7-3.8V, equivalent to 0.011-0.019 kWh. This provides 8-12 hours of active usage.

Tablet Batteries

Tablets usually feature 6,000-10,000 mAh batteries at 3.7V, translating to 0.022-0.037 kWh, supporting 10-15 hours of mixed use.

Power Banks

Portable chargers range from 10,000-30,000 mAh at 3.7V internal (5V output), providing 0.037-0.111 kWh to charge multiple devices.

Laptop Batteries

Laptop batteries typically offer 40,000-100,000 mAh at 11.1-14.8V, equivalent to 0.444-1.48 kWh for 4-10 hours of operation.

Electric Vehicle Packs

EV battery packs contain modules with hundreds of thousands of mAh at high voltages (200-800V), totaling 40-100+ kWh for 200-400 mile range.

Solar Power Stations

Portable solar generators feature 50,000-300,000 mAh capacity at 12-48V, providing 0.6-14.4 kWh for off-grid applications.

Related Energy Conversions

mAh to Wh

Formula: Wh = mAh × V ÷ 1,000
Direct conversion without the kilo prefix, commonly used for smaller batteries.

mAh to Ah

Formula: Ah = mAh ÷ 1,000
Converts milliamp-hours to amp-hours, standard unit for larger batteries.

kWh to mAh

Formula: mAh = kWh × 1,000,000 ÷ V
Reverse conversion when energy capacity is known in kilowatt-hours.

Wh to kWh

Formula: kWh = Wh ÷ 1,000
Simple unit conversion between watt-hours and kilowatt-hours.

Ah to kWh

Formula: kWh = Ah × V ÷ 1,000
Converts amp-hour capacity to energy with voltage consideration.

kWh to Joules

Formula: J = kWh × 3,600,000
Converts electrical energy to SI unit joules for scientific calculations.

Why Voltage Matters in Conversion

Milliamp-hours (mAh) measure electric charge capacity—how much current a battery can deliver over time. Kilowatt-hours (kWh) measure energy—the actual work potential of that charge. The crucial difference is voltage.

Electric Charge × Voltage = Energy

Two batteries with identical mAh ratings can store vastly different amounts of energy if their voltages differ.

For instance, a 10,000 mAh battery at 3.7V stores 0.037 kWh, while the same 10,000 mAh at 12V stores 0.12 kWh—more than three times the energy. This is why laptop batteries with lower mAh ratings can outlast smartphone batteries with higher mAh values.

Common battery voltages include:

3.7V: Standard lithium-ion cells in smartphones and tablets
3.8V: High-density lithium-polymer batteries
5V: USB charging standard and power bank outputs
11.1V / 14.8V: Laptop battery packs (3-4 cells in series)
12V / 24V / 48V: Automotive, marine, and solar energy systems
400V / 800V: Electric vehicle high-voltage battery architectures

Applications in Real-World Scenarios

Airline Travel Restrictions

Airlines typically limit portable batteries to 100 Wh (0.1 kWh) without approval, with an absolute maximum of 160 Wh (0.16 kWh). A 20,000 mAh power bank at 5V equals 100 Wh—exactly at the limit. At 3.7V, that same capacity is only 74 Wh, well within regulations.

Solar Energy Storage

A residential solar power station with 100,000 mAh at 48V stores 4.8 kWh. This can power a refrigerator (150W) for 32 hours, LED lighting (50W) for 96 hours, or a laptop (60W) for 80 hours during grid outages.

Electric Vehicle Range

An EV with a 60 kWh battery pack operating at 400V has an effective capacity of 150,000,000 mAh (150 Ah). At 200 Wh/mile efficiency, this provides approximately 300 miles of range on a single charge.

Off-Grid Camping

A camping setup with a 30,000 mAh portable station at 12V (0.36 kWh) can run a 12V cooler (40W) for 9 hours, charge 8 smartphones (15 Wh each), or power LED camping lights (5W) for 72 hours.

Frequently Asked Questions

What is the difference between mAh and kWh?

mAh (milliamp-hours) measures electric charge capacity—the quantity of electrical charge a battery can store. kWh (kilowatt-hours) measures energy—the actual work potential. Energy equals charge multiplied by voltage. A battery’s mAh rating tells you its charge capacity, but only when combined with voltage can you calculate its energy storage in kWh.

Can I convert mAh to kWh without knowing voltage?

No, voltage is essential for this conversion. mAh measures charge while kWh measures energy, and the relationship between them requires voltage (kWh = mAh × V ÷ 1,000,000). Without voltage, you cannot determine how much energy the battery stores. Always check the battery specifications for voltage information.

How many mAh equal 1 kWh at common voltages?

At 3.7V: 270,270 mAh equals 1 kWh. At 5V: 200,000 mAh equals 1 kWh. At 12V: 83,333 mAh equals 1 kWh. At 24V: 41,667 mAh equals 1 kWh. At 48V: 20,833 mAh equals 1 kWh. The required mAh decreases as voltage increases because energy is the product of charge and voltage.

Why do power banks show both mAh and Wh ratings?

Power banks display mAh because consumers are familiar with this metric from smartphone batteries, making it easier to compare capacities. They also show Wh (or kWh for larger units) because aviation regulations and energy calculations require this measurement. The internal battery voltage (typically 3.7V) differs from the output voltage (typically 5V), so both ratings provide complete information.

Is a higher mAh rating always better?

Not necessarily. While higher mAh indicates greater charge capacity, actual energy storage depends on voltage. A 10,000 mAh battery at 12V (120 Wh) stores more energy than a 20,000 mAh battery at 3.7V (74 Wh). Consider both mAh and voltage, or simply compare kWh or Wh ratings directly for accurate energy capacity comparison.

How does this conversion help with solar power systems?

Solar power stations are rated in Wh or kWh, while individual battery cells are often specified in mAh. Converting mAh to kWh helps you calculate total system capacity when building or expanding solar storage, estimate backup runtime for appliances, compare different battery configurations, and determine how many solar panels you need for adequate charging.

What voltage should I use for lithium-ion batteries?

Standard lithium-ion cells have a nominal voltage of 3.6-3.7V. Lithium-polymer (LiPo) batteries often use 3.7V or 3.8V. When batteries are connected in series, voltages add up: two cells make 7.4V, three make 11.1V, four make 14.8V. Always check the manufacturer’s specifications, as nominal voltage can vary slightly between battery chemistries.

How accurate is the mAh rating on batteries?

Reputable manufacturers provide accurate ratings within 5-10% tolerance. However, actual capacity degrades over charge cycles and varies with temperature, discharge rate, and age. Budget batteries, especially from unknown brands, may overstate capacity by 20-50%. Always purchase from trusted manufacturers and expect gradual capacity loss over the battery’s lifetime.

Battery Chemistry Comparison

Battery Type	Nominal Voltage	Energy Density	Typical Applications
Lithium-Ion (Li-ion)	3.6-3.7V	150-250 Wh/kg	Smartphones, laptops, EVs
Lithium-Polymer (LiPo)	3.7-3.8V	130-200 Wh/kg	Drones, RC vehicles, thin devices
Lithium Iron Phosphate (LiFePO4)	3.2V	90-160 Wh/kg	Solar storage, power stations, EVs
Lead-Acid	2V per cell (12V system)	30-50 Wh/kg	Automotive, backup power, solar
Nickel-Metal Hydride (NiMH)	1.2V	60-120 Wh/kg	Hybrid vehicles, rechargeable AA/AAA

Calculation Steps

Follow these steps to manually convert mAh to kWh:

Locate the battery capacity in milliamp-hours (mAh) from the device specifications or battery label
Find the nominal voltage (V) rating, typically printed on the battery or listed in technical specifications
Multiply the mAh value by the voltage: mAh × V
Divide the result by 1,000,000 to convert to kilowatt-hours: (mAh × V) ÷ 1,000,000
Round to an appropriate number of decimal places (typically 3-4 places for accuracy)
Verify the result makes sense for the application (smartphone: 0.01-0.02 kWh, laptop: 0.4-1.5 kWh, EV: 40-100 kWh)

Quick Check Method

For 3.7V batteries, divide mAh by 270,000 to get approximate kWh. For 5V systems, divide by 200,000. This provides a fast mental estimate.