Few consumer shopping tasks are more confusing than replacing a button cell battery. Every major battery brand—Renata, Sony/Murata, Maxell, Energizer, Seiko, and Rayovac—historically assigned proprietary model numbers to identical physical battery sizes.
In this master reference guide, we provide a complete cross-reference chart matching every popular watch and small coin cell, explain how to read battery nomenclature codes, and break down Silver Oxide versus Alkaline chemistry.
Master Watch Battery Cross-Reference Chart
| Common Standard Code | Renata / Swiss | Energizer / US | Maxell / Sony | Chemistry | Dimensions (Dia x Hgt mm) | Typical Use |
|---|---|---|---|---|---|---|
| 377 | 377 | 377 / 376 | SR626SW | Silver Oxide 1.55V | 6.8 x 2.6 mm | Most common quartz watches (Fossil, Timex, Casio) |
| 364 | 364 | 364 / 363 | SR621SW | Silver Oxide 1.55V | 6.8 x 2.1 mm | Slim women’s dress watches |
| 371 | 371 | 371 / 370 | SR920SW | Silver Oxide 1.55V | 9.5 x 2.0 mm | Chronograph watches, date displays |
| 395 | 395 | 395 / 399 | SR927SW | Silver Oxide 1.55V | 9.5 x 2.7 mm | Luminox, Swiss Army, diver watches |
| 321 | 321 | 321 / 322 | SR616SW | Silver Oxide 1.55V | 6.8 x 1.6 mm | Ultra-thin luxury dress watches |
| 394 | 394 | 394 / 380 | SR936SW | Silver Oxide 1.55V | 9.5 x 3.6 mm | Seiko kinetic, heavy chronographs |
| 357 | 357 | 357 / 303 | SR44W | Silver Oxide 1.55V | 11.6 x 5.4 mm | Vintage digital watches, precision calipers |
| LR44 (A76) | LR44 | A76 | AG13 / LR1154 | Alkaline 1.50V | 11.6 x 5.4 mm | Calculators, laser pointers, digital thermometers |
| CR2032 | CR2032 | CR2032 | DL2032 | Lithium 3.0V | 20.0 x 3.2 mm | Car key fobs, computer motherboards (CMOS), AirTags |
| CR2025 | CR2025 | CR2025 | DL2025 | Lithium 3.0V | 20.0 x 2.5 mm | Slim key fobs, car stereo remotes |
| CR2016 | CR2016 | CR2016 | DL2016 | Lithium 3.0V | 20.0 x 1.6 mm | Casio G-Shock backlight, digital scales |
| CR2450 | CR2450 | CR2450 | DL2450 | Lithium 3.0V | 24.5 x 5.0 mm | Smart home sensors (Philips Hue, Aqara), BMW fobs |
How to Decode Coin Cell Battery Names
International Electrotechnical Commission (IEC) designations tell you the exact chemistry and physical dimensions if you know the code:
Lithium Cells (e.g., CR2032):
- C: Chemistry = Lithium Manganese Dioxide (3.0 Volts)
- R: Shape = Round / Cylindrical
- 20: Diameter = 20.0 millimeters
- 32: Thickness = 3.2 millimeters
Silver Oxide vs. Alkaline Button Cells:
- SR: Silver Oxide chemistry (1.55V). Provides a completely flat discharge voltage curve, ensuring watch quartz crystals oscillate at exact frequencies until the cell is exhausted.
- LR: Alkaline chemistry (1.50V). Voltage slopes downward continuously under load from 1.50V to 1.10V, causing quartz watches to lose time or stop prematurely.
Low Drain (SW) vs. High Drain (W) Watch Batteries
Notice the suffix letters on Silver Oxide batteries:
- SW (Low Drain): Engineered for standard analog watches with 2 or 3 hands and no additional functions. The chemical electrolyte optimizes low self-discharge for 3 to 5 years.
- W (High Drain): Engineered for chronographs, digital backlights (Indiglo), vibration alarms, and chime functions. High-drain cells have lower internal resistance to deliver brief pulses of current without voltage collapse.
Frequently Asked Questions
Can I put a cheaper LR44 alkaline battery in a watch that calls for a 357 / SR44?
You can physically fit it because dimensions are identical (11.6 x 5.4 mm), but you shouldn’t. An LR44 alkaline battery outputs 1.50V and its voltage drops steadily over its life, causing your watch to lose minutes per month. The silver oxide 357 maintains a constant 1.55V output and lasts nearly twice as long without risk of alkaline electrolyte leakage.
Can I use a CR2032 in place of a CR2025?
Both are 20mm diameter, 3V lithium cells. However, the CR2032 is 3.2mm thick while the CR2025 is 2.5mm thick (0.7mm thinner). In some devices with flexible spring contacts (like a computer motherboard), a CR2032 can fit. But in precision-molded car key fobs, forcing a CR2032 can crack the circuit board or prevent the plastic housing from snapping shut.
Why do watch batteries leak and ruin watch movements?
As batteries discharge to near 0%, internal chemical reactions generate hydrogen gas, increasing internal pressure until the seal breaches. Silver oxide batteries use potassium hydroxide (KOH) or sodium hydroxide (NaOH) electrolyte; when leaked, it corrodes gold and brass gears. To prevent this, always remove dead batteries immediately.
How do I replace a watch battery without scratching the case back?
For snap-back cases, use a dedicated watch knife or case opener tool (never a kitchen knife) inserted into the small case notch. For screw-off case backs, use an adjustable two-prong or three-prong case wrench. Always handle the new silver oxide cell using plastic tweezers or latex finger cots; handling batteries with metal tweezers creates an instantaneous short circuit across the positive rim and negative cap.
Related Reading: For more in-depth testing, see our guide on Coin Cell & Button Batteries Guide.
