CR2016, CR2025 and CR2032 share a diameter and nominal voltage, but not the same thickness
The three names look almost interchangeable because all three are 20 mm lithium coin cells. Their last two digits point to different thicknesses: 1.6 mm, 2.5 mm and 3.2 mm. That mechanical difference is enough to make a substitution wrong for some battery holders even when the nominal voltage matches.
How the numbers help you decode the size
For these common CR coin cells, the four-digit size code is a compact clue to the physical dimensions. The first two digits indicate a nominal diameter of 20 mm. The final two digits correspond to thickness in tenths of a millimeter: 16 means roughly 1.6 mm, 25 means roughly 2.5 mm, and 32 means roughly 3.2 mm.
That pattern makes the names easier to remember, but it should not be treated as a complete compatibility rule. Chemistry, terminal arrangement, device requirements, holder pressure, operating current, and manufacturer specifications still matter.
Side-by-side comparison
| Cell | Nominal diameter | Nominal thickness | Example Energizer capacity rating* |
|---|---|---|---|
| CR2016 | 20 mm | 1.6 mm | 90 mAh |
| CR2025 | 20 mm | 2.5 mm | 163 mAh |
| CR2032 | 20 mm | 3.2 mm | 240 mAh |
*Capacity figures above are manufacturer-specific example ratings from Energizer documentation under stated test conditions. Capacity varies with manufacturer, load, cutoff voltage, temperature, age and application.
Why the thicker cell often has more capacity
When diameter and chemistry family are held broadly similar, a thicker cell can contain more active material. That is why the example CR2032 rating is higher than the CR2025 rating, and the CR2025 rating is higher than the CR2016 rating.
But “more capacity” does not make the thicker cell a universal upgrade. A battery holder is a mechanical system. Its spring force, cover clearance, contact geometry and retention method are designed around a particular thickness or range. A cell that is 0.7 mm or 1.6 mm thicker can change contact pressure substantially in a small compartment.
Similarly, a thinner substitute can fit loosely, lose contact when the device moves, or fail to remain clamped by the holder. Mechanical fit is therefore a first-class specification, not a cosmetic detail.
Same nominal voltage does not mean interchangeable
CR2016, CR2025 and CR2032 lithium manganese-dioxide coin cells are commonly specified at a nominal 3 V. That shared voltage is useful, but it answers only one part of the compatibility question.
A device designer may have chosen a particular cell because of thickness, expected runtime, pulse-current behavior, internal resistance, contact design, temperature range, or other operating requirements. If the device manual or battery compartment calls for CR2032, that label is more authoritative than a visual guess that another 20 mm cell “looks close enough.”
Why stacking thinner cells is not a substitute for one thicker cell
Do not use simple arithmetic on thickness to justify stacking cells. Two 1.6 mm cells may be close to the physical thickness of one 3.2 mm cell, but electrically they are a different circuit. Cells stacked in series add voltage, so two nominal 3 V cells would create a very different electrical condition from a single nominal 3 V cell.
The device should use the cell count and battery type specified by its manufacturer. Mechanical similarity is not electrical equivalence.
Capacity numbers need context
Battery capacity is not a fixed bucket that every device can use identically. Energizer's lithium coin handbook explicitly notes that delivered capacity depends on device drain rate and cutoff voltage. A device that stops operating at a relatively high voltage can leave some potential capacity unused. Higher drain can also change effective performance.
This is why a 240 mAh rating should not be turned directly into “this device will run for exactly 240 hours at 1 mA.” That division is a first-order arithmetic estimate, not a complete battery model. Real behavior depends on the discharge curve, load pattern and device cutoff.
What the CR prefix tells you
The CR designation is associated with lithium manganese-dioxide coin cells in the IEC naming system used by manufacturers. It is not merely a shape code. A similar physical size with a different chemistry prefix can have different electrical and discharge characteristics.
That means a cross-reference table should be read carefully. A retailer may group several commercial labels around a common standardized size, but a device specification should still be the starting point.
Practical substitution checklist
- Read the device label or manual. Use the specified battery type when available.
- Match the full cell designation. Do not stop at “3 V lithium coin cell.”
- Check thickness. CR2016, CR2025 and CR2032 differ materially even though their diameter is the same.
- Do not force a battery holder. Excess pressure is evidence that the mechanical fit is wrong, not a reason to push harder.
- Do not stack cells to imitate thickness. Cell count changes the electrical circuit.
- Treat capacity as application-dependent. Manufacturer mAh ratings are measured under defined conditions.
Why CR2025 and CR2032 are so often confused
They share the same 20 mm diameter and are both common in key fobs, small electronics, calculators, watches and other compact devices. When viewed from the top, the diameter dominates the appearance, while the 0.7 mm thickness difference is easy to miss.
That makes them a good example of why product specifications need to be read dimension by dimension. The front face can look identical while the side profile changes the entire mechanical fit.
What to do when the old battery is missing
If there is no original cell to read, look for markings inside the battery compartment, molded text on a cover, the device manual, or the manufacturer's support documentation. A generic web forum or a visually similar cell should be a fallback source, not the first source.
If the holder itself clearly carries a cell code, that is usually more useful than trying to estimate thickness by eye. Small differences are difficult to judge without a measuring tool.
Related battery guides
- CR2025 vs CR2032 narrows the comparison to the two sizes people most often confuse and adds manufacturer capacity examples.
- CR2032 vs BR2032 shows the opposite problem: the outer size can stay the same while the chemistry family changes.
Primary sources
This guide explains specifications and sizing. For a real device, the manufacturer's battery requirement takes priority.