357 vs 303
Both are 11.6 × 5.4 mm silver oxide cells at 1.55 V. The codes once separated high-drain (357, SR44W) from low-drain (303, SR44SW) construction; most are now sold dual-marked.
These are the same size and the same silver oxide chemistry at 1.55 volts, and most shops now sell them as one cell marked "357/303". The two numbers originally marked different internal builds: 357 for devices that draw current in bursts, 303 for a watch that sips it slowly. In practice either will run either job. Buy whichever is on the shelf.
- Verdict:
- Same size and chemistry — originally high-drain against low-drain
- Interchangeable:
- yes — the same cell under two codes
Side-by-side specifications
| Specification | 357 | 303 |
|---|---|---|
| Chemistry | Silver Oxide | Silver Oxide |
| Type | Button Cell | Button Cell |
| Nominal voltage | 1.55 V | 1.55 V |
| Diameter | 11.6 mm | 11.6 mm |
| Height | 5.4 mm | 5.4 mm |
| Typical capacity | 150–190 mAh | 150–175 mAh |
| Rechargeable | No | No |
| Also sold as | SR44W, SR44, V357, SG13 | SR44SW, D303, V303 |
Size comparison
Both cells share an identical 11.6 × 5.4 mm footprint, so physical fit is not the deciding factor here.
What the codes meant
357 is SR44W and 303 is SR44SW. The W and SW suffixes mark high-drain and low-drain constructions, which differ in the electrolyte inside rather than in size, voltage or chemistry.
What they mean now
Most manufacturers build one cell that satisfies both duties and print both numbers on the packet. Where only one number appears, it will still run a watch or a calculator.
Neither is the alkaline one
Both are silver oxide at 1.55 V. The alkaline cell in the same shell is the LR44, also sold as AG13 or A76, at 1.5 V.
Can I use a 303 instead of a 357?
Yes. The 357 and the 303 are the same cell — 11.6 × 5.4 mm, 1.55 V, silver oxide. The two codes come from different naming schemes, not from different batteries, so whichever you find on the shelf will work.
Check before you swap. Batteries with similar dimensions are not always interchangeable. Always verify voltage, chemistry and the requirements printed in your device manual before fitting a replacement.