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Amp-Hours to kWh Calculator

Convert battery capacity from amp-hours (Ah) to kilowatt-hours (kWh). Essential for comparing batteries, sizing solar systems, and understanding EV range.

Calculate kWh from Amp-Hours

Battery Capacity (Ah)

Battery Voltage (V)

Common voltages: 12V, 24V, 36V, 48V

Ah to kWh Formula

kWh = (Ah × V) ÷ 1000

Where kWh is energy in kilowatt-hours, Ah is capacity in amp-hours, and V is voltage in volts.

Example

A 100 Ah battery at 12V:
kWh = (100 × 12) ÷ 1000 = 1.2 kWh

What Is Ah to kWh Conversion?

Ampere-hours (Ah) and kilowatt-hours (kWh) are both units of electrical energy storage, but they measure different aspects of battery capacity. Ah measures charge capacity — how much current a battery can deliver over time. kWh measures total energy capacity by factoring in voltage. The conversion formula is: kWh = Ah × V ÷ 1000. This relationship is fundamental in battery engineering, electric vehicle (EV) range estimation, and solar energy storage system design. Understanding this conversion helps engineers and consumers compare batteries of different voltages on an equal energy basis.

How to Calculate Ah to kWh Conversion

1
Enter Battery Capacity in Ah
Input the ampere-hour rating found on your battery label. Common values: 100Ah for deep-cycle batteries, 50-80Ah for car batteries, 2-5Ah for power tool batteries.
2
Enter Battery Voltage
Input the nominal voltage of your battery system. Standard voltages include 12V (automotive), 24V (marine/RV), 36V (golf carts), and 48V (solar/telecom systems).
3
Review the kWh Result
The calculator multiplies Ah by voltage and divides by 1000 to give kilowatt-hours. For example, a 100Ah 12V battery stores 1.2 kWh of energy.
4
Compare Energy Storage
Use the kWh value to compare batteries across different voltage platforms and estimate runtime for your electrical loads.

Why Ah to kWh Conversion Matters

Electric Vehicle Range Planning

EV manufacturers specify battery capacity in kWh (e.g., Tesla Model 3 has 57.5-82 kWh). Converting Ah to kWh helps compare EV battery packs across different voltage architectures.

Solar Energy Storage Sizing

Off-grid solar systems require precise energy storage calculations. Converting battery bank Ah ratings to kWh ensures your storage meets daily energy consumption needs.

UPS System Design

Uninterruptible power supply systems must provide enough energy during outages. Converting Ah to kWh helps determine backup runtime for critical loads like servers and medical equipment.

Cost-Per-kWh Analysis

Comparing battery costs on a per-kWh basis ($/kWh) enables fair price comparisons between lithium-ion, lead-acid, and other battery chemistries regardless of voltage.

Electrical Safety Tips & Best Practices

Use Nominal Voltage

Always use the nominal (rated) voltage, not the fully charged voltage. A "12V" lead-acid battery charges to 14.4V but its nominal voltage is 12V for energy calculations.

Account for Depth of Discharge

Usable energy is less than total capacity. Lead-acid batteries should only be discharged to 50% (multiply kWh by 0.5), while lithium-ion can safely reach 80-90% depth of discharge.

Temperature Affects Capacity

Battery capacity decreases in cold temperatures. A battery rated at 100Ah at 25°C may only deliver 80Ah at 0°C. Factor in ambient temperature for accurate energy estimates.

Series vs Parallel Connections

Batteries in series increase voltage (same Ah), while parallel connections increase Ah (same voltage). Both configurations change the total kWh of your battery bank.

Ah to kWh Conversion Chart

Capacity (Ah)	12V	24V	36V	48V
10 Ah	0.12 kWh	0.24 kWh	0.36 kWh	0.48 kWh
20 Ah	0.24 kWh	0.48 kWh	0.72 kWh	0.96 kWh
50 Ah	0.6 kWh	1.2 kWh	1.8 kWh	2.4 kWh
100 Ah	1.2 kWh	2.4 kWh	3.6 kWh	4.8 kWh
150 Ah	1.8 kWh	3.6 kWh	5.4 kWh	7.2 kWh
200 Ah	2.4 kWh	4.8 kWh	7.2 kWh	9.6 kWh
300 Ah	3.6 kWh	7.2 kWh	10.8 kWh	14.4 kWh
400 Ah	4.8 kWh	9.6 kWh	14.4 kWh	19.2 kWh
500 Ah	6 kWh	12 kWh	18 kWh	24 kWh

Common Battery Capacities

Battery Type	Capacity	Voltage	Energy
Car Battery	50-80 Ah	12V	0.6-0.96 kWh
Deep Cycle RV	100-200 Ah	12V	1.2-2.4 kWh
Golf Cart Battery	150-225 Ah	6V	0.9-1.35 kWh
Tesla Powerwall	~275 Ah	48V	13.5 kWh
EV Battery (Small)	~60 Ah	400V	24 kWh
EV Battery (Large)	~100 Ah	400V	40 kWh
Laptop Battery	4-6 Ah	11.1V	0.04-0.07 kWh
E-Bike Battery	10-20 Ah	36-48V	0.36-0.96 kWh

Frequently Asked Questions

How many kWh is a 100 Ah 12V battery?

A 100 Ah battery at 12V has 1.2 kWh of total capacity. However, usable capacity is typically 0.6 kWh for lead-acid (50% DoD) or about 1 kWh for lithium (80% DoD).

How long will a battery run my device?

Divide the usable kWh by your device's wattage. For example, a 1.2 kWh battery running a 100W device: 1.2 ÷ 0.1 = 12 hours theoretically. Account for inverter efficiency (multiply by 0.85-0.9).

What's better: higher Ah or higher voltage?

For the same kWh, higher voltage systems have advantages: less current means thinner wires, lower losses, and more efficient inverters. This is why EVs use 400V+ systems.

How do I calculate solar battery needs?

Determine daily energy use in kWh, then factor in desired days of autonomy, depth of discharge, and system losses. For example: 5 kWh/day × 2 days × 1.25 (losses) ÷ 0.5 (DoD) = 25 kWh battery bank.

How many kWh is a 200Ah 12V battery?

A 200Ah 12V battery stores 2.4 kWh of total energy (200 × 12 ÷ 1000 = 2.4). However, usable energy depends on battery chemistry — lead-acid provides about 1.2 kWh usable (50% DoD), while lithium provides about 2.0-2.16 kWh usable (80-90% DoD).

What is the difference between Ah and kWh?

Ah (ampere-hours) measures electrical charge capacity without considering voltage, while kWh (kilowatt-hours) measures total energy by incorporating voltage. Two batteries with the same Ah but different voltages store different amounts of energy. kWh provides a universal energy comparison metric.

How do I calculate kWh for a battery bank?

For batteries in series, add voltages and use total voltage × Ah ÷ 1000. For parallel batteries, add Ah ratings and use single battery voltage × total Ah ÷ 1000. For series-parallel combinations, calculate total voltage and total Ah first, then convert.

Why do EV batteries use kWh instead of Ah?

EV batteries use kWh because it directly represents usable energy regardless of pack voltage architecture. Different EV manufacturers use different voltages (400V, 800V), so kWh provides a standardized comparison of driving range and energy capacity across all electric vehicles.

How many Ah do I need for 1 kWh?

The Ah needed depends on voltage: at 12V you need 83.3Ah, at 24V you need 41.7Ah, at 48V you need 20.8Ah. Higher voltage systems require fewer ampere-hours for the same energy storage, which is why higher voltage battery systems use thinner cables.

References & Industry Standards

IEEE 1188 - Recommended Practice for Maintenance, Testing, and Replacement of VRLA Batteries
IEC 61960 - Secondary Lithium Cells and Batteries for Portable Applications
National Electrical Code (NEC) Article 480 - Storage Batteries
SAE J1772 - Electric Vehicle Charging Standards

Last updated: 2026-02-01 | Reviewed by UnitTables Engineering Team

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What Is Ah to kWh Conversion?

How to Calculate Ah to kWh Conversion

Enter Battery Capacity in Ah

Input the ampere-hour rating found on your battery label. Common values: 100Ah for deep-cycle batteries, 50-80Ah for car batteries, 2-5Ah for power tool batteries.

Enter Battery Voltage

Input the nominal voltage of your battery system. Standard voltages include 12V (automotive), 24V (marine/RV), 36V (golf carts), and 48V (solar/telecom systems).

Review the kWh Result

The calculator multiplies Ah by voltage and divides by 1000 to give kilowatt-hours. For example, a 100Ah 12V battery stores 1.2 kWh of energy.

Compare Energy Storage

Use the kWh value to compare batteries across different voltage platforms and estimate runtime for your electrical loads.

Why Ah to kWh Conversion Matters

Electric Vehicle Range Planning

EV manufacturers specify battery capacity in kWh (e.g., Tesla Model 3 has 57.5-82 kWh). Converting Ah to kWh helps compare EV battery packs across different voltage architectures.

Solar Energy Storage Sizing

Off-grid solar systems require precise energy storage calculations. Converting battery bank Ah ratings to kWh ensures your storage meets daily energy consumption needs.

UPS System Design

Uninterruptible power supply systems must provide enough energy during outages. Converting Ah to kWh helps determine backup runtime for critical loads like servers and medical equipment.

Cost-Per-kWh Analysis

Comparing battery costs on a per-kWh basis ($/kWh) enables fair price comparisons between lithium-ion, lead-acid, and other battery chemistries regardless of voltage.

Electrical Safety Tips & Best Practices

Use Nominal Voltage

Always use the nominal (rated) voltage, not the fully charged voltage. A "12V" lead-acid battery charges to 14.4V but its nominal voltage is 12V for energy calculations.

Account for Depth of Discharge

Usable energy is less than total capacity. Lead-acid batteries should only be discharged to 50% (multiply kWh by 0.5), while lithium-ion can safely reach 80-90% depth of discharge.

Temperature Affects Capacity

Battery capacity decreases in cold temperatures. A battery rated at 100Ah at 25°C may only deliver 80Ah at 0°C. Factor in ambient temperature for accurate energy estimates.

Series vs Parallel Connections

Batteries in series increase voltage (same Ah), while parallel connections increase Ah (same voltage). Both configurations change the total kWh of your battery bank.

Ah to kWh Conversion Chart

Capacity (Ah)	12V	24V	36V	48V
10 Ah	0.12 kWh	0.24 kWh	0.36 kWh	0.48 kWh
20 Ah	0.24 kWh	0.48 kWh	0.72 kWh	0.96 kWh
50 Ah	0.6 kWh	1.2 kWh	1.8 kWh	2.4 kWh
100 Ah	1.2 kWh	2.4 kWh	3.6 kWh	4.8 kWh
150 Ah	1.8 kWh	3.6 kWh	5.4 kWh	7.2 kWh
200 Ah	2.4 kWh	4.8 kWh	7.2 kWh	9.6 kWh
300 Ah	3.6 kWh	7.2 kWh	10.8 kWh	14.4 kWh
400 Ah	4.8 kWh	9.6 kWh	14.4 kWh	19.2 kWh
500 Ah	6 kWh	12 kWh	18 kWh	24 kWh

Common Battery Capacities

Battery Type	Capacity	Voltage	Energy
Car Battery	50-80 Ah	12V	0.6-0.96 kWh
Deep Cycle RV	100-200 Ah	12V	1.2-2.4 kWh
Golf Cart Battery	150-225 Ah	6V	0.9-1.35 kWh
Tesla Powerwall	~275 Ah	48V	13.5 kWh
EV Battery (Small)	~60 Ah	400V	24 kWh
EV Battery (Large)	~100 Ah	400V	40 kWh
Laptop Battery	4-6 Ah	11.1V	0.04-0.07 kWh
E-Bike Battery	10-20 Ah	36-48V	0.36-0.96 kWh

Frequently Asked Questions

How many kWh is a 100 Ah 12V battery?

A 100 Ah battery at 12V has 1.2 kWh of total capacity. However, usable capacity is typically 0.6 kWh for lead-acid (50% DoD) or about 1 kWh for lithium (80% DoD).

How long will a battery run my device?

Divide the usable kWh by your device's wattage. For example, a 1.2 kWh battery running a 100W device: 1.2 ÷ 0.1 = 12 hours theoretically. Account for inverter efficiency (multiply by 0.85-0.9).

What's better: higher Ah or higher voltage?

For the same kWh, higher voltage systems have advantages: less current means thinner wires, lower losses, and more efficient inverters. This is why EVs use 400V+ systems.

How do I calculate solar battery needs?

How many kWh is a 200Ah 12V battery?

What is the difference between Ah and kWh?

How do I calculate kWh for a battery bank?

Why do EV batteries use kWh instead of Ah?

How many Ah do I need for 1 kWh?

References & Industry Standards

IEEE 1188 - Recommended Practice for Maintenance, Testing, and Replacement of VRLA Batteries

IEC 61960 - Secondary Lithium Cells and Batteries for Portable Applications

National Electrical Code (NEC) Article 480 - Storage Batteries

SAE J1772 - Electric Vehicle Charging Standards

Last updated: 2026-02-01 | Reviewed by UnitTables Engineering Team