AA battery Size & Weight

An AA battery is 50.5 mm long and 14.5 mm in diameter (IEC designation R6 / LR6). An alkaline AA weighs about 23 grams; lithium AAs are lighter at ~15 g and rechargeable NiMH cells are heavier at ~28 – 31 g. The size is fixed by international standard, so every brand fits the same slot.

This guide covers the exact AA dimensions, how they compare to AAA, C, and D cells, why the positive terminal sticks out, and how an AA sizes up against a coin and a lipstick.

Quick Answer: How Big Is an AA Battery?

An AA cell is 50.5 mm tall and 14.5 mm across, with a small ~5.5 mm positive nub on top included in that height (the flat negative end and the body are 14.5 mm wide). Alkaline weight is ~23 g.

AA Battery Dimensions at a Glance

• Length: 50.5 mm max (some cells are 49.2 – 50.5 mm); devices allow for the full 50.5 mm
• Diameter: 13.5 – 14.5 mm; 14.5 mm is the nominal figure
• IEC / ANSI names: R6 (carbon-zinc), LR6 (alkaline), FR6 (lithium), HR6 (NiMH), all the same size
• A 4-pack stood side by side is about 58 x 50.5 x 14.5 mm
• Terminal: raised button positive, flat negative, so cells only seat one way

What Does an AA Battery Look Like in Size?

An AA is a bit shorter than a AAA-plus-a-quarter and about the length of a house key. Its 14.5 mm diameter is close to a pencil with the wood, or a little narrower than a US penny. Four AAs in a row span about 58 mm, roughly the length of a large chicken egg.

6 Everyday Comparisons for an AA Battery

1. A AAA battery (44.5 x 10.5 mm) is 6 mm shorter and 4 mm narrower than an AA.
2. A C battery (50 x 26.2 mm) is the same height but nearly twice the diameter.
3. A D battery (61.5 x 34.2 mm) is 11 mm taller and much wider.
4. A US penny (19.05 mm) is wider than an AA is thick.
5. A house key (~50 – 55 mm) is close to an AA’s length.
6. A lipstick (~70 – 85 mm) is taller and similar in diameter.

AA Battery Size in Different Units

Battery Sizes Compared

C and D cells are the same chemistry as an AA, just larger to hold more material and deliver more current for longer, which is why a torch on D cells outlasts one on AAs.

Common Mistakes When Comparing AA Battery Dimensions

1. Assuming all AA cells weigh the same. Lithium AAs (~15 g) are much lighter than alkaline (~23 g) or NiMH (~28 g), even though they are the same size.
2. Ignoring the terminal nub in the length. The 50.5 mm includes the raised positive button.
3. Thinking a C cell is taller than an AA. They are the same height; the C is just fatter.
4. Confusing “AA” with “2A” or “double-A” branding. They all mean the same R6 size.
5. Forcing a slightly long cell. Some heavy-duty cells run to the full 50.5 mm; a tight compartment may need the shorter end of the range.

Frequently Asked Questions

What are the dimensions of an AA battery?

50.5 mm long and 14.5 mm in diameter.

How much does an AA battery weigh?

About 23 g for alkaline, ~15 g for lithium, ~28 g for rechargeable NiMH.

Is an AA battery bigger than a AAA?

Yes, 6 mm longer and 4 mm wider.

Is a C battery the same height as an AA?

Yes, both are about 50 mm tall; the C is much wider.

What is the IEC name for an AA battery?

R6 for carbon-zinc, LR6 for alkaline, FR6 for lithium, HR6 for NiMH.

Why does one end of the battery stick out?

The raised button is the positive terminal; the flat end is negative, so the cell only fits one way.

Final Takeaway

An AA battery is 50.5 mm long and 14.5 mm across (IEC R6), with alkaline cells weighing about 23 grams, lithium ~15 g, and NiMH ~28 g at the same size. C and D cells share the chemistry but are fatter to run longer, and the raised nub on top is the positive terminal.