AA vs AAA Battery: The Difference Between AA And AAA Batteries

AA and AAA batteries are very popular cylindrical batteries available in various chemistries, each offering different discharge characteristics.

AA and AAA batteries differ in size and hence the capacity. In certain situations, using a special battery holder, one may replace AA with AAA batteries, but at the expense of battery capacity.

Updated: January 14, 2023.

AA and AAA Batteries Features and Specifications

The main difference between AA and AAA batteries is in physical dimensions.

AA batteries feature physical dimensions of 14.5 x 50.5 mm, while AAA batteries feature physical dimensions of 10.5 x 44.5 mm.

Also, these batteries differ in volume:

• AA battery volume: ~8.3 cm³, ~0.506 inch³
• AAA battery volume: ~3.8 cm³, ~0.232 inch³

Because of the physical differences, AA and AAA batteries of the same chemistry have different internal resistance - AA batteries have lower internal resistance.

Thus, due to the larger physical dimensions of AA batteries, AA batteries generally feature a larger capacity and can provide stronger discharge currents.

Note: output voltages depend on the exact chemistry type, and when the batteries are not under load, the output voltage of the batteries is the same, regardless of the physical dimensions.

For historical reasons, AA and AAA batteries feature a nominal voltage of 1.5 volts, the voltage of the first Zinc-Carbon AA batteries, practically the oldest AA and AAA battery types.

The following comparison tables list some of the most popular AA and AAA battery chemistries, with their most important features and specifications.

AA Batteries Chemistries Comparison Table

AAA Batteries Chemistries Comparison Table

As one can see, when the same battery chemistries are compared, the capacities of AA and AAA batteries differ.

Zinc Carbon AA vs. AAA battery: Zinc Carbon batteries are non-rechargeable batteries with a nominal voltage of 1.5V and nominal capacity of 500-600 mAh for AAA and 600-1600 mAh for AA batteries.

Actual capacity depends on the battery age, temperature, discharge current, and similar. Zinc Carbon batteries are cheap and reliable batteries, but they have short storage life (eventually they will leak), they are unable to provide stronger currents without capacity loss, and similar.

Most Zinc Carbon AA and AAA batteries are used in cheaper toys and similar applications, but even there, they are being phased out by alkaline AA and AAA batteries.

Alkaline AA vs. AAA battery: Alkaline batteries are non-rechargeable batteries that feature a nominal voltage of 1.5V and nominal capacity of 850-1200 mAh for AAA and 1800-2700 mAh for AA batteries.

Alkaline AA and AAA batteries are the most common non-rechargeable AA and AAA batteries and some of the most common batteries on the market.

Li-FeS₂ AA vs. AAA battery: Li-FeS₂ or Lithium Iron Disulfide batteries are types of non-rechargeable AAA and AA lithium batteries featuring a typical voltage of 1.5 V, excellent capacity, and very long shelf life of up to or even more than 20 years.

The Open Circuit Voltage (OCV) of Li-FeS₂ batteries is 1.8V, but as soon as the batteries are discharged, the actual voltage drops to 1.5V.

AAA Li-FeS₂ batteries feature a typical capacity of 1100-1300 mAh, while AA Li-FeS2 batteries feature a typical capacity of 2700-3300 mAh.

Both AAA and AA Li-FeS2 batteries are used in high-drain applications and in stand-by applications where batteries must reliably operate even after years of not being used.

Li-Ion AA vs. AAA battery: Li-Ion AA and AAA batteries are rechargeable batteries based on several lithium-ion chemistries with voltage ranging from 3.2 to 3.7 volts and capacities of 350-600 mAh for AAA and 600-2000+ mAh for AA batteries.

Due to their voltage of 3.2 - 3.7 volts, Li-Ion AA and AAA batteries are not backward compatible with 1.5V AA and AAA batteries.

But, since lithium-ion AA and AAA batteries offer many advantages over non-rechargeable AA and AAA batteries, some devices support the use of both 1.5V non-rechargeable Zinc-Carbon, alkaline, and other 1.5V batteries, 3V non-rechargeable lithium batteries, and 3.2-3.7V rechargeable batteries.

Such devices are mostly LED flashlights and photo cameras, and similar equipment.

Note: 1.5V battery may be replaced with a 3.0-3.7V battery only if explicitly allowed by the device's manufacturer! Otherwise, voltage differences can damage or even destroy the device intended ONLY for 1.5V AA and AAA batteries.

For more information about this topic, feel free to check our Types of Lithium Battery Chemistries article.

Lithium 1.5V AA vs. AAA battery: In order to make rechargeable lithium-ion batteries compatible with 1.5V AA and AAA battery devices, some manufacturers offer lithium-ion batteries with control electronics that convert the battery's internal 3.2-3.7V down to 1.5V.

Such batteries feature a nominal capacity of 400-600 mAh for AAA batteries and 1000-2000+ mAh for AA lithium 1.5V batteries.

To recharge them, such batteries either feature a USB charging plug or a micro-USB charging port/receptacle.

NiCd AA vs. AAA battery: Nickel Cadmium AA and AAA batteries are some of the oldest types of rechargeable AA and AAA batteries.

NiCd batteries feature a nominal voltage of 1.2 volts and a nominal capacity of 300-500 mAh for AAA and 600-1000 mAh for AA batteries.

Although NiCd batteries are cheap, reliable, and are able to provide very strong currents, they also suffer from a strong memory effect, contain toxic metals, and support a relatively small number of charging/discharging cycles.

These are the reasons why NiCd batteries are being phased out in favor of low self-discharge Nickel Metal-Hydride (NiMH) batteries.

NiMH AA vs. AAA battery: Nickel Metal-Hydride (NiMH) AAA and AA batteries are very popular types of rechargeable AAA and AA batteries, featuring a nominal voltage of 1.2V and nominal capacity of 600-1300 mAh for AAA and 700-2800 mAh for AA batteries.

Modern NiMH batteries practically have no memory effect, can provide relatively strong currents, have a very low self-discharge rate, and since they don't contain mercury, lead, cadmium, and similar toxic elements, they are environment-friendly batteries - nonetheless, they must be recycled properly after they die.

Some NiMH battery types support up to 2000 or even more charging/discharging cycles when being charged with proper battery chargers and when NOT being discharged with extra strong currents.

For more information about these batteries, feel free to check our Nickel Metal Hydride (NiMH) Battery Chemistry article.

Li-SOCl₂ AA vs. AAA battery: Lithium Thionyl Chloride (Li-SOCl₂) AAA and AA batteries are types of non-rechargeable batteries featuring a nominal voltage of 3.5-3.6 volts, OCV (Open Circuit Voltage) of ~3.65 volts, and nominal capacity of 600-800 mAh for AAA and 2400-2700 mAh for AA batteries.

Lithium Thionyl Chloride (Li-SOCL₂) AAA and AA batteries are not directly compatible with 1.5V batteries and should NOT be used in devices intended ONLY for 1.5V AA batteries.

But, devices that may use both 1.5V and 3.0-3.7V batteries may benefit from their high energy density and extra-long shelf life.

NiOOH AA vs. AAA battery: Nickel Oxy-Hydroxide (NiOOH) AAA and AA batteries are actually sub-type of alkaline batteries where nickel oxyhydroxide is added to the manganese dioxide, leading to the 1.5 V typical voltage during high drain use and 1.7 V OCV voltage.

NiOOH AAA and AA batteries have a very similar capacity to standard alkaline batteries (1000-1200 mAh for AAA and 2200-2700 mAh for AA batteries), but they can be drained using larger currents without significant capacity loss and are often used in high drain devices like cameras and other photo equipment.

NiZn AA vs. AAA battery: Nickel Zinc (NiZn) rechargeable AAA and AA batteries feature a nominal voltage of ~1.6V and a capacity of 500-700 mAh for AAA and 1500-1800 mAh for AA batteries.

NiZn batteries feature a relatively low self-discharge rate and good discharge characteristics.

Although NiZn batteries are generally backward compatible with 1.5V batteries, note that some devices intended for NiMH batteries (1.2V) may get damaged if, for example, four NiMH batteries (4.8V) are replaced with four NiZn batteries (6V).

Frequently Asked Questions (FAQ)

Here are some of the most common Frequently Asked Questions (FAQ) about AA and AAA batteries.

What lasts longer, AA or AAA batteries?

AA batteries are larger and have larger capacity and lower internal resistance, hence they last longer, assuming that both AA and AAA batteries are of the same chemistry.

Is an AA battery stronger than AAA?

Yes, due to lower internal resistance and larger volume (and internal surface), AA batteries are able to provide stronger currents with lower voltage drop, when compared with AAA batteries.

Again, it is assumed that the AA and AAA batteries are of the same battery chemistry.

Can you use AA batteries instead of AAA?

No, AA batteries are larger than AAA batteries, and they cannot fit the AAA batteries' compartments.

How many AAA batteries equal an AA battery?

Roughly, 2-2.5 AAA batteries are equal in capacity to a single AA battery.

Can you use AAA batteries as AA?

Generally, yes, using AAA to AA battery adapter, one can use an AAA battery instead of an AA battery.

Just be aware that the AAA battery features lower capacity and is unable to provide as strong currents as an AA battery.

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Long Story Short: While AAA and AA batteries are not directly replaceable due to the physical differences, each of these battery sizes is available in many different chemistries, each differing in voltage, capacity, shelf-life, price, discharge characteristics, and similar.

Most devices designed around AAA and AA batteries require and operate properly with 1.5V AAA and AA batteries, however, some of them may benefit from switching to lithium 3.0-3.7V batteries if the device support such batteries.

If not, You may choose 1.5V lithium AAA and AA batteries with built-in DC-to-DC converters, which lower the voltage down to 1.5V.

If You are unsure about the exact battery chemistry that your device supports, be sure and check its Owner's Guide or manual - better safe than sorry ...