CR2032 vs CR2025 vs CR2016 vs CR1632: The Complete Coin Cell Battery Guide

If you've ever tipped out a drawer of spare batteries and struggled to tell a CR2032 from a CR2025, you're not alone. These small, round, silver "coin cell" batteries all look nearly identical, and picking the wrong one is one of the most common battery mix-ups there is. This guide compares the four most widely used sizes — CR2032, CR2025, CR2016 and CR1632 — so you can find the right one for your device the first time.

All four are 3V lithium batteries, but they differ in size and capacity. Here's how they compare:

The codes aren't random. "CR" refers to the battery's chemistry — lithium manganese dioxide. The numbers that follow give you the dimensions: the first two digits are the diameter in millimetres, and the last two are the thickness in tenths of a millimetre. So a CR2032 is 20mm across and 3.2mm thick, while a CR1632 is a smaller 16mm across but the same 3.2mm thickness. Once you know this code, you can work out the size of almost any coin cell battery without needing to measure it.

The CR2032 is the most widely used coin cell battery, and the one most people mean when they just say "watch battery" or "button battery" — even though it's rarely used in watches themselves. Its larger capacity and thicker profile make it the go-to choice for car key fobs, computer motherboards (where it keeps the BIOS clock running), remote controls, and small household electronics like kitchen scales and LED candles.

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The CR2025 has the same 20mm diameter as the CR2032 but is thinner, giving it a lower capacity in exchange for fitting into slimmer devices. It's commonly specified in smaller remote controls, some calculators, and compact electronics where every millimetre of case depth counts.

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The thinnest of the 20mm-diameter batteries, the CR2016 trades capacity for a very slim profile. You'll typically find it specified in slim remote controls, small calculators, and low-drain devices like flashing LED lights, where its shorter runtime isn't a practical drawback.

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Unlike the other three, the CR1632 has a genuinely different diameter — 16mm rather than 20mm — while keeping the same 3.2mm thickness as a CR2032. It's a popular choice for smaller and older car key fobs, glucose meters, and other compact electronics that need a slightly smaller cell.

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• All four run at 3 volts and use lithium manganese dioxide chemistry.
• None of them are rechargeable — they're designed for single use.
• All have a long shelf life, typically 5–10 years when stored unused.
• All are classed as "button" or "coin cell" batteries due to their flat, round shape.

• Diameter: CR2032, CR2025 and CR2016 all share a 20mm diameter. The CR1632 is smaller, at 16mm.
• Thickness: This is what really separates CR2032 (3.2mm), CR2025 (2.5mm) and CR2016 (1.6mm) from each other.
• Capacity and runtime: Thicker batteries pack in more capacity. A CR2032 will typically outlast a CR2016 several times over in the same device.

This is the question most people are really asking — and the honest answer is sometimes, but check first.

• CR2032, CR2025 and CR2016 share the same 20mm diameter, so a CR2032 will often physically fit in a compartment designed for a CR2025 or CR2016, provided there's enough depth in the battery compartment and the contacts can still reach it. Many device manufacturers explicitly allow this as an upgrade, since the voltage is identical and you simply get a longer-lasting battery. Going the other way — using a thinner CR2016 in a CR2032 slot — will usually work electrically, but the battery may sit loose unless the compartment has a spring contact to take up the gap, and it will run out much sooner.
• CR1632 has a different diameter entirely, so it is not a straightforward swap for any of the 20mm batteries, even though the voltage matches. Forcing a battery of the wrong diameter into a holder can damage the contacts or stop the device sealing properly.

The safest approach is always to check the code printed on the old battery, or check your device's manual, rather than assuming by shape or size alone.

There are two different "lifespans" to think about. Shelf life — how long an unused battery keeps its charge in storage — is typically 5–10 years for all four types. In-use life depends entirely on the device: a car key fob used a few times a day might run for one to three years on a single CR2032, while a continuous-drain device like an LED light will get through a battery far faster, and a lower-capacity CR2016 will always need replacing sooner than a CR2032 in the same application.

Coin cell batteries are a genuine swallowing hazard for young children and pets — their small size and shiny appearance make them easy to mistake for a sweet or coin, and a swallowed lithium coin cell can cause serious internal injury within hours. Store spare batteries out of reach and in their original packaging, and dispose of used batteries responsibly rather than in general household waste. See our guide to common battery questions for more on safe handling and disposal.

If you're not sure which of the four you need, the most reliable method is to check the code embossed on the old battery itself — it will be printed directly on the flat face. If the old battery isn't available, your device's manual or manufacturer's website will usually specify the exact type. When in doubt, take the old battery along when you buy a replacement so you can compare it directly.