Amp Hour Calculator

Select

Simple Advance

I want to calculate

Watt-hours

Voltage

kJ ▾

C-rate

This free amp hour calculator is created to easily convert watts into amp hours and assist with accurate battery capacity calculations.

How Does Our Amp Hour Calculator Work?

Here’s a quick guide to using this battery ampere calculator:

Input:

Simple Mode:

Choose the parameter you want to compute from the first dropdown menu
Fill in the required values in their respective input fields
Click the calculate button to see the results

Advanced Mode:

Enter the load power and current in the designated fields
Optionally, adjust battery type, age, and temperature factors
Hit the calculate button once all inputs are provided

Output: The amp hour battery calculator will display:

Battery capacity, runtime until fully charged, and discharge current ratios
Recommended battery amps needed to power your selected load

What is a Battery Amp Hour?

In electrical engineering, “One Amp Hour (Ah) represents the charge flowing through a battery in one hour.” This 12V battery amp hour calculator is designed specifically for this calculation.

Formula to Calculate Battery Capacity

Understanding battery Ah calculations is simple using these formulas:

P = V * I

E = V * I * T (Power multiplied by Time equals Energy)

E = V * Q (Current over time equals total charge)

These equations are applied in our battery amp hours calculator to determine battery Ah accurately.

How to Calculate Amp Hours Manually

You can calculate battery capacity if you know the voltage and stored energy without using an amp hour calculator:

Consider a standard 12V battery
Determine the energy stored, e.g., 27 Wh
Use the formula:

E = V * Q

Q = 27 / 12

Q = 2.25 Ah

Practical Example

Scenario:

Suppose you have a 20V battery storing around 20Wh. How can you determine its amp hours?

Solution:

Using the formula, the battery amp hours can be calculated as follows:

E = V * Q

20 = 20 * Q

Q = 1 Ah

The free battery Ah calculator performs these calculations instantly, saving your time and effort.

Amp Hour Usage Chart:

Below is a chart showing amp hour consumption of various devices over different operating times (1h, 2h, 4h, 8h). Review it to plan your battery usage efficiently.

Device Wattage	Ah Needed For 1h Run Time	Ah Needed For 2h Run Time	Ah Needed For 4h Run Time	Ah Needed For 8h Run Time
10 Watt	0.83 Ah (830 mAh)	1.67 Ah	3.33 Ah	6.67 Ah
20 Watt	1.67 Ah	3.33 Ah	6.67 Ah	13.33 Ah
50 Watt	4.17 Ah	8.33 Ah	16.67 Ah	33.33 Ah
100 Watt	8.33 Ah	16.67 Ah	33.33 Ah	66.67 Ah
150 Watt	12.50 Ah	25.00 Ah	50.00 Ah	100.00 Ah
200 Watt	16.67 Ah	33.33 Ah	66.67 Ah	133.33 Ah
250 Watt	20.83 Ah	41.67 Ah	83.33 Ah	166.67 Ah
300 Watt	25.00 Ah	50.00 Ah	100.00 Ah	200.00 Ah
350 Watt	29.17 Ah	58.33 Ah	116.67 Ah	233.33 Ah
400 Watt	33.33 Ah	66.67 Ah	133.33 Ah	266.67 Ah
450 Watt	37.50 Ah	75.00 Ah	150.00 Ah	300.00 Ah
500 Watt	41.67 Ah	83.33 Ah	166.67 Ah	333.33 Ah
600 Watt	50.00 Ah	100.00 Ah	200.00 Ah	400.00 Ah
700 Watt	58.33 Ah	116.67 Ah	233.33 Ah	466.67 Ah
800 Watt	66.67 Ah	133.33 Ah	266.67 Ah	533.33 Ah
900 Watt	75.00 Ah	150.00 Ah	300.00 Ah	600.00 Ah
1,000 Watt	83.33 Ah	166.67 Ah	333.33 Ah	666.67 Ah
1,500 Watt	125.00 Ah	250.00 Ah	500.00 Ah	1,000.00 Ah
2,000 Watt	166.67 Ah	333.33 Ah	666.67 Ah	1,333.33 Ah
2,500 Watt	208.33 Ah	416.67 Ah	833.33 Ah	1,666.67 Ah
3,000 Watt	250.00 Ah	500.00 Ah	1,000.00 Ah	2,000.00 Ah
4,000 Watt	333.32 Ah	666.68 Ah	1,333.33 Ah	2,666.68 Ah
5,000 Watt	416.65 Ah	833.35 Ah	1,666.67 Ah	3,333.35 Ah
10,000 Watt	833.33 Ah	1,666.67 Ah	3,333.33 Ah	6,666.67 Ah

This battery amp hour calculator can also serve as a quick tool to cross-check all the values listed in the chart above. Handy, isn’t it?

FAQs

How many Ah does a 12V car battery have?

Typically, a 12V car battery has a capacity around 50Ah. You can confirm this easily using this battery amp hour calculator.

How long can a 100Ah battery power a TV?

A 100Ah battery can run a 32-inch LED TV for approximately 30 minutes, and a 50-inch LED TV for about 15 minutes.

How many solar panels are needed to charge a 100Ah battery?

A 610W solar panel setup is generally sufficient to recharge a 100Ah lithium-ion battery. Keep in mind this estimate assumes ideal peak sunlight conditions.

How many amps can a 12V battery supply?

A standard 12V battery can provide up to 600A per hour, which can also be verified with this amp hour battery calculator.

References:

Sources consulted for this guide include: Wikipedia – Ampere hour, Other electric charge measures; Khan Academy – Electrical current and units; Lumen Learning – Current and Drift Velocity; LibreTexts – Electric Current and Voltage Measurements