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.
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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.
How the two constructions differed
The W and SW suffixes marked cells tuned for high and low current draw, using different electrolytes internally. A high-drain cell suits a camera meter that fires in bursts; a low-drain one suits a watch that sips continuously for years. Same size, same chemistry, different internal recipe.
Why the distinction has faded
Manufacturing improved to the point where one cell serves both duties well enough, so most makers now build a single product and print both numbers on it. A packet reading 357/303 is not a supplier hedging its bets — it is an accurate description of what is inside.
When it is still worth matching
Vintage camera meters and some laboratory instruments were designed around one variant and their manuals say so. If yours names 303 or SR44SW specifically, honour it. For a watch bought this century, either number will do.
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.
357 vs 303: common questions
Is the 303 a direct replacement for the 357?
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.
What is the difference between the 357 and the 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. In short: same size and chemistry — originally high-drain against low-drain.
Are the 357 and the 303 the same size?
Yes. Both measure 11.6 × 5.4 mm, so either fits where the other does. Whether they are interchangeable is an electrical question, not a physical one.
Which lasts longer, the 357 or the 303?
The 357. It is rated at 150–190 mAh against 150–175 mAh for the 303 — roughly 1.0× the capacity, though real runtime depends on how much current your device draws.
Background reading
The wider questions behind these two codes.
Silver oxide for precision, alkaline for price
Not alternatives — different voltages for different jobs
L is alkaline, S is silver oxide — the number after is the size
One size, two chemistries — the 357 and 303 are the same cell