Quick Coin Battery Guide

Pretty much everyone is familiar with the sizing for your typical alkaline batteries, like AA, AAA, D, and so on. But their more discrete cousins, the coin cell batteries, seem to be a little less easy to tell apart just by looking at them, and they all seem to have some strange cypher of numbers and letters on them. Worry not! This post will give you a quick rundown on how to translate all that balderdash.

On coin cell batteries you’ll find a code that consists of two letters, followed by four (sometimes three) numbers. This particular naming convention conforms to the current International Electrotechnical Commission (IEC) standard, though there are coin cells that conform to an older standard and are named differently.


The first of the two letters is used to indicate what type of battery it is. The second letter, the R, is just an indicator of the shape (cylindrical). The various chemistries are listed below in cathode/anode (+/-) order. (The lithium batteries here are not rechargeable lithium-ion, they just contain lithium)

  • B – Carbon-monofluoride/Lithium
  • C – Manganese-dioxide/Lithium
  • G – Copper-oxide/Lithium
  • L – Manganese-dioxide/Zinc
  • M,N – Mercuric-oxide/Zinc
  • P – Oxygen/Zinc (zinc-air battery)
  • S – Silver-oxide/Zinc

The numbers following the first two letters are an indication of the battery’s dimensions. Diameter in millimeters is indicated by the first two, in a four digit code, or just the first in a three digit code. The last two numbers indicate the height of the battery in tenths of a millimeter.



As you can see (allowing for some manufacturing tolerances for the dimensions) the size indicated on the battery is pretty spot on 20mm wide and 1.6mm tall. Well, that’s about it, folks. Now you can amaze your friends at parties by telling them what coin cell battery codes mean……or not.


About Nate Eastland

I am currently a student at Washington State University studying Electrical Engineering. I am originally from Southern California but I have spent most of my life in the Seattle area. Growing up I was always deeply interested in the pure sciences like chemistry and physics. Throughout high school I began to look for ways that I could apply the theory I had learned. I chose to pursue engineering so that my interest in applied sciences could be used to solve real world problems.

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8 Comments on “Quick Coin Battery Guide”

  1. Hey, FYI… when you stack coin cells, you risk having a bunch of dead batteries, or worse, melting the box they are in :-).

  2. You missed out few letters in your explanation. Even the batteries in you photo are CR and four digits. The C (according to your explanation means manganese-dioxide/lithium), but what’s the R? The battery I’m holding is a DL 2025 which I’m guessing is manganese-dioxide/zinc based on your description. But what’s the D? Is that for Duracell? It’s a Duracell battery. Is a DR2025 interchangeable for a CR2025?

    1. I have to replace a coin battery in my door bell, it says 3v lithium & has the number 1411 on the back, what shall I look for when buying another?

    2. The R, I think he mentioned earlier in the post, was the description of the shape of the battery. So R, I’ll assume, would stand for “round”. As for the D, I even double checked before answering, so I can definitely say yes, it does stand for Duracell. So yeah, so long as the sizes are the same (20 mm in diameter and 2.5 mm in hight), they’ll be interchangeable, even if the first letters are different, cuz that’s only telling what the battery was made with so unless it’s a specialized piece using the battery and requires specific battery types right down to the mixture in the battery, you’ll be good to go.

  3. Hi Nate,

    Great article! I didn’t know how to identify a battery I needed to replace in a mini stick PC but you guide made is so simple to understand! Thanks a million!

    Ps. Needed a very small CR-1220 c”,)

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