Watch battery size chart
The same battery is sold under three or four names. This chart lines them up so you can buy the right one, or send the watch to us and skip the guesswork.
Silver-oxide and lithium cross reference
| Number | SR / IEC code | Alkaline equivalent | Size (mm, dia × height) | Typical use |
|---|---|---|---|---|
| 377 | SR626SW | AG4 | 6.8 × 2.6 | Very common in small and mid-size quartz watches |
| 376 | SR626W | AG4 | 6.8 × 2.6 | Same size as 377, high-drain version for analog-digital watches |
| 364 | SR621SW | AG1 | 6.8 × 2.1 | Thin watches, kids' watches |
| 371 | SR920SW | AG6 | 9.5 × 2.1 | Common in men's quartz watches |
| 370 | SR920W | AG6 | 9.5 × 2.1 | High-drain version of 371 |
| 395 | SR927SW | AG7 | 9.5 × 2.7 | Common in men's quartz watches |
| 399 | SR927W | AG7 | 9.5 × 2.7 | High-drain version of 395 |
| 397 | SR726SW | AG2 | 7.9 × 2.6 | Common in women's watches |
| 379 | SR521SW | AG0 | 5.8 × 2.1 | Very small women's watches |
| 317 | SR516SW | — | 5.8 × 1.6 | Very small, thin women's watches |
| 321 | SR616SW | — | 6.8 × 1.6 | Thin women's watches |
| 362 | SR721SW | AG11 | 7.9 × 2.1 | Thin quartz watches |
| 373 | SR916SW | — | 9.5 × 1.6 | Thin men's watches |
| 315 | SR716SW | — | 7.9 × 1.6 | Thin dress watches |
| 394 | SR936SW | AG9 | 9.5 × 3.6 | Larger watches |
| 392 | SR41W | AG3 | 7.9 × 3.6 | Larger and older watches |
| 357 | SR44W | AG13 | 11.6 × 5.4 | Older digital watches, calculators |
| CR2016 | CR2016 | — | 20 × 1.6 | 3-volt lithium. Many digital and sport watches |
| CR2025 | CR2025 | — | 20 × 2.5 | 3-volt lithium. Digital, sport and some G-Shock models |
| CR2032 | CR2032 | — | 20 × 3.2 | 3-volt lithium. Larger digital and sport watches |
| CR1220 | CR1220 | — | 12.5 × 2.0 | 3-volt lithium. Some digital watches |
Silver-oxide cells are 1.55 volts. The CR lithium cells are 3 volts and are not interchangeable with silver-oxide cells, even when the diameter looks close.
How to find the battery your watch takes
- Read the old battery. Open the caseback and look at the number printed on the cell. This is the only sure way.
- Check the caseback or manual. Some brands print the battery type there.
- Look up the movement. The caliber number on the movement (for example a Seiko or Miyota number) plus "battery" in a search usually gives the answer.
Screw-down backs, snap backs with no lip and water-resistant cases are easy to scratch or leave leaking. If you don't have a case knife and a press, it's often cheaper to mail it in for $20 than to buy the tools.
Watches that don't take a regular battery
- Citizen Eco-Drive and Seiko Solar charge from light. If one stops, it usually needs light, not a battery. See Citizen Eco-Drive stopped?
- Seiko Kinetic uses a rechargeable capacitor charged by wrist movement. An old one may need a new capacitor, which is a repair, not a battery swap.
- Automatic and hand-wound watches have no battery at all.
Common questions
How do I find out which battery my watch takes?
The easiest way is to open the case and read the number stamped on the old battery. Some casebacks or manuals list the battery too. You can also search the movement caliber number, printed on the movement, with the word "battery".
Is a 377 the same as an SR626SW?
Yes. 377 is the number most brands print on the pack, and SR626SW is the standard (IEC) code for the same 6.8 × 2.6 mm silver-oxide cell. AG4 is the cheaper alkaline version of the same size, which usually runs out sooner.
What is the difference between SW and W batteries?
SW cells are low drain, for ordinary analog watches. W cells are high drain, for watches with a backlight, alarm or digital display. Use the type your watch had in it.
How long does a watch battery last?
Usually two to five years in an analog quartz watch. Chronographs, alarms and backlights use it up faster. A watch that has sat in a drawer drains it the same as one on your wrist.