You’re digging through a junk drawer. You find a dead car key fob or a kitchen scale that’s finally given up the ghost. You pop the back off and find a tiny, silver disc staring at you. It says CR2032. Or maybe it says DL2032. Or just 5004LC. Suddenly, you’re staring at a button cell battery size chart on your phone, trying to figure out if the 2025 you found in the back of the cabinet will work instead of the 2032 you actually need.
Spoilers: It won't. Well, it might fit, but it’ll rattle around and lose connection because it’s thinner.
These little powerhouses are everywhere. They run our pacemakers, our Tile trackers, and those annoying singing birthday cards. But the naming conventions? They're a mess. It’s a mix of chemistry, dimensions, and brand-specific vanity codes that make buying a replacement feel like a scavenger hunt. Honestly, the system is designed by engineers for engineers, leaving the rest of us squinting at tiny engraved numbers under a kitchen light.
Why the button cell battery size chart feels like a secret code
Most people think a battery is just a battery. But with button cells—also called coin cells—the name is literally the blueprint. If you see a lithium battery labeled CR2032, the "CR" tells you it's Lithium Manganese Dioxide. The "20" is the diameter in millimeters. The "32" is the height—3.2 millimeters.
It’s logical. It’s precise. Yet, for some reason, we still have manufacturers like Duracell or Energizer slapping their own labels on things. A silver oxide 357 battery is the same size as an LR44, but the chemistry is different, meaning your high-drain device might die in a week if you swap them.
Breaking down the CR vs. LR vs. SR confusion
You’ve got three main players in the button cell world. First, there's Lithium (CR). These are the flat, wide ones. They usually put out 3 volts and last for years on a shelf. They’re the gold standard for things that need to stay powered for a long time but don't pull a lot of juice at once.
Then you have Alkaline (LR). These are the cheap ones. You’ll find them in kids' toys or those tiny LED flashlights. They usually start at 1.5 volts but drop off pretty quickly as they die. If you’re looking at a button cell battery size chart, you’ll see LR44 listed alongside about ten other names. It’s the most common alkaline button cell on the planet.
Finally, there’s Silver Oxide (SR). These are the "watch batteries." They are more expensive than alkaline but they hold a very steady voltage until the very end of their life. This is crucial for digital watches or medical devices like glucose monitors where a voltage drop could mean an inaccurate reading.
The chart that actually makes sense
Instead of a massive table that makes your eyes bleed, let’s look at the "Big Three" sizes that account for about 90% of what you’ll actually encounter in the wild.
The 20mm King: The CR2032.
It’s 20mm wide and 3.2mm thick. If you have a PC, it’s on your motherboard. If you have a car, it’s in your remote. If you try to use a CR2025 (20mm wide, 2.5mm thick) or a CR2016 (20mm wide, 1.6mm thick), they are the same width but too skinny. You might get them to work by folding up a piece of aluminum foil to bridge the gap, but that’s a fire hazard waiting to happen. Don't do it.
The LR44 / SR44 / 357 / A76.
This is the chunky one. It’s 11.6mm wide and 5.4mm thick. If you’re using it in a cheap laser pointer, get the LR44. If you’re using it in a vintage Nikon camera or a high-end calipers, spend the extra two bucks for the Silver Oxide (SR44 or 357). The camera’s light meter will actually stay accurate with the silver oxide version.
The Tiny Ones: CR1632 and CR1220.
These show up in smaller fobs and certain sensors. The CR1632 is 16mm wide, 3.2mm thick. The CR1220 is 12mm wide, 2.0mm thick. They are surprisingly hard to find at a gas station, so you usually have to order them online.
Why names vary by brand
Companies love to be special. Energizer uses "ECR" prefixes. Rayovac uses "CR." Duracell often uses "DL." If you see DL2032, it is 100% interchangeable with a CR2032. The "DL" just stands for Duracell Lithium. It’s branding masquerading as technical data.
Renata, a Swiss company owned by Swatch Group, dominates the watch battery market. They use their own numbering system. A Renata 377 is the same as a SR626SW. If you’re a watch enthusiast, you basically have to keep a cross-reference guide bookmarked because the industry refused to standardize for decades.
Chemistry matters more than you think
You can’t just go by the button cell battery size chart and pick whatever fits the hole. Voltage is the dealbreaker.
Most lithium cells are 3.0V.
Most alkaline and silver oxide cells are 1.5V or 1.55V.
If you find a way to jam two 1.5V alkaline batteries into a space meant for one 3V lithium (which sometimes happens in weirdly designed battery compartments), you might be okay on voltage, but the physical fit will be terrible. Conversely, if you put 3V where 1.5V is expected, you might fry the circuit. Always check the voltage stamped on the old battery. If you can't read it because it's corroded, Google the device model number.
The Zinc-Air anomaly
There’s a fourth type: Zinc-Air. These are almost exclusively for hearing aids. They have a little colored tab on the back (usually orange, brown, or blue). Once you pull that tab, oxygen enters the battery and "turns it on."
They have a huge energy density but they die in weeks regardless of use once they're unsealed. You cannot swap these for any other type, and a button cell battery size chart will usually list them separately because their discharge curve is so unique.
Safety: The thing nobody wants to talk about but should
Button cells are dangerous. Not because they explode—though they can if you try to recharge a non-rechargeable one—but because they are the perfect size for a toddler to swallow.
When a lithium coin cell gets stuck in the esophagus, it creates an electrical circuit with the moist tissue. This causes a chemical reaction that can burn through the esophagus in as little as two hours. This isn't just "battery acid leaking." It's an electrochemical burn.
If you have kids, look for batteries with "bitterant" coatings. Brands like Duracell coat their 2032s in a substance that tastes so foul it forces a child to spit it out instantly. Also, look for the "Lithium Coin Cell Safety Act" (Reese's Law) compliant packaging, which requires those frustrating child-proof blisters that require scissors to open.
How to read the numbers like a pro
Next time you look at a button cell battery size chart, remember this quick mental math for the "CR" series:
- First two digits: Diameter (mm)
- Last two digits: Thickness (0.1 mm)
So, a CR2450?
24mm wide. 5.0mm thick.
It’s a beast. Usually found in high-drain LED remotes or smart home hubs.
What about the SR series? It’s more chaotic. An SR626SW:
The "6" is roughly the diameter (6.8mm).
The "26" is the height (2.6mm).
The "SW" means it's for low-drain devices (like a watch with just hands).
If it said "W," it would be for a watch with an alarm or a light.
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Buying advice: Don't get ripped off
Buying these at the grocery store check-out is a scam. They charge $5 or $10 for a single battery.
Buy them in "tear strips" of 5 or 10 online. You can get a 10-pack of CR2032s for the price of one at a retail pharmacy. Just check the "use by" date. Lithium cells have a shelf life of 8 to 10 years, so buying in bulk is actually smart. Alkaline button cells, however, tend to leak if they sit for more than 2 or 3 years. Only bulk-buy lithium.
Actionable steps for your battery drawer
Stop guessing. If you want to handle your battery needs like an expert, do these three things right now:
- Get a universal battery tester. A cheap analog tester that handles 1.5V and 3V button cells will save you from throwing away perfectly good batteries that just had a poor connection in the device.
- Tape your spares. If you store button cells loose in a bag or drawer, they can touch each other. If a stack forms, they can short out, drain, or in rare cases, heat up. Keep them in the original blister pack or put a small piece of scotch tape over one side.
- Check the "W" vs "SW" on watch batteries. If your watch has a backlight, you must use a "High Drain" (W) silver oxide battery. Using a "Low Drain" (SW) version will cause the watch to reset every time you hit the light button because the voltage will sag too low.
Identify the code on your dead battery, match the first two letters for chemistry, and ensure the numbers align with the physical space. If the code is rubbed off, measure the diameter with a ruler; that's usually enough to get you 90% of the way through a button cell battery size chart to find your match.