Batteries are in our daily lives, from laptops to kids’ toys, and not a day goes by without using any kind of battery. When choosing a battery for any kind of device, it’s important to take the battery’s kind into consideration, ensuring that the battery fits. 

Mainly, there are two kinds of batteries that are most commonly used: the double A (AA) and triple A (AAA). Each one of them has its own characteristics and usages, and although they are similar in voltage, they differ in size, capacity and application. 

This guide provides a detailed comparison of both kinds, so you won’t feel overwhelmed when you choose the right battery next time. 

What Is an AA Battery? 

An AA battery, a double battery, is a standard-sized, cylindrical single-cell or dry-cell battery, commonly used in small household devices, such as remote controls, clocks, toys, and flashlights. It measures approximately 50.5 millimeters in length and 14.5 millimeters in diameter, with a positive terminal marked by a small protrusion and a flat negative terminal.

AA batteries come in both disposable types, such as alkaline, which typically provide 1.5 volts, and rechargeable types, such as nickel–metal hydride (NiMH) or lithium-ion, which can offer different voltages. The “AA” designation refers to the battery’s size standard, not its chemistry, making it interchangeable across devices designed to fit this specification. Even though many newer kinds are now available, AA batteries remain relevant due to their consistency and durability. 

What Is an AAA Battery?

On the other hand, the triple-A battery, AAA, is even smaller in size and used in compact electronic devices such as TV remotes, wireless computer mice, digital thermometers, and handheld electronics. It measures about 44.5 millimeters in length and 10.5 millimeters in diameter, making it slimmer and shorter than the more common AA battery.

Like AA batteries, AAA cells have a protruding positive terminal and a flat negative terminal, and they are available in both disposable types (such as alkaline, typically 1.5 volts) and rechargeable types (such as nickel–metal hydride, usually 1.2 volts). Moreover, their small size allows for more flexible design options in portable devices, enabling manufacturers to create sleeker and lighter products. 

AA vs AAA Batteries: Main Differences

When putting both into comparison, they offer significant advantages and characteristics; however, the main difference can be seen in the following: 

• Size 

• AA: About 50.5 mm long and 14.5 mm in diameter.
• AAA: About 44.5 mm long and 10.5 mm in diameter.

• Capacity and Power

• AA batteries generally have a higher energy capacity (more mAh), meaning they can power devices for a longer time before running out.
• AAA batteries have less capacity, so they’re suited for devices that need less power.

• Common Uses

• AA: Medium-to-high drain devices like toys, flashlights, portable radios and gaming controllers.
• AAA: Low-drain devices like remote controls, small clocks and wireless computer mice.

• Weight 

• AA batteries are heavier due to their size and more stored energy.
• AAA batteries are lighter and more compact.

Practical Uses of AA and AAA Batteries

At first, a double A battery has a medium to high power demand, meaning that they are suitable for devices that need more power, such as toys, flashlights, headlamps, gaming controllers (Xbox) and wireless keyboards and mice. 

On the other hand, with its smaller size, a triple A battery is more fit for devices that require less power. Usually, it is used for TV & AC remotes, small medical devices, LED fairy lights and clocks. 

Can You Substitute AA Batteries for AAA Batteries?

The answer is no. Even though they are similar in chemistry, their different size makes it difficult to substitute. When inserting batteries into a wall clock, AA batteries slide easily into place, ensuring proper contact with the terminals. AAA batteries would rattle loosely, failing to establish a reliable connection, leading to a malfunctioning clock.

FAQs

1. Are AA and AAA batteries the same voltage?

Yes. Most AA and AAA batteries provide 1.5 volts in their disposable form (alkaline) and around 1.2 volts in rechargeable versions (NiMH). The main difference lies in their size and energy capacity, not the voltage.

2. Which lasts longer, AA or AAA batteries?

AA batteries generally last longer because they have a larger capacity. This allows them to power medium-to-high-drain devices for extended periods compared to AAA batteries, which are better for low-drain devices.

3. Can I replace AAA batteries with AA batteries?

No. Although they have the same voltage, their physical sizes are different, so they won’t fit interchangeably in most devices without an adapter. Using the wrong size can cause poor contact and device malfunction.

4. How do I choose between AA and AAA batteries for my device?

Check your device’s battery compartment and manual. Devices that need more power, like toys or gaming controllers, usually require AA batteries, while low-power devices, like remotes or clocks, often use AAA batteries.