LR44 and 357 are not the same battery, but they are physically compatible in most devices

An LR44 and a 357 battery have the same physical size and shape — both are button cells 11.6 mm in diameter and 5.4 mm thick — so one will fit into the slot designed for the other. However, they are chemically different. An LR44 is an alkaline battery, while a 357 is a silver oxide battery. This difference matters for how long they last, how much power they deliver, and whether your device will work the same way with either one.

The short answer for most people: you can swap them in a pinch, but a 357 will last longer and cost more, while an LR44 is cheaper and adequate for many low-drain devices like calculators and watches. If your device came with one type, that is usually the better choice to replace it with.

Key Takeaways

  • LR44 and 357 batteries are the same physical size but different chemistries — alkaline versus silver oxide — so they fit the same slot but perform differently.
  • A 357 battery lasts two to three times longer than an LR44 in the same device and maintains more stable voltage as it drains.
  • LR44 batteries are cheaper and work fine in low-power devices like calculators, toys, and basic watches.
  • If your device originally came with a 357, replacing it with an LR44 may cause it to work less reliably or shut off sooner than expected.
  • Some precision instruments and hearing aids require a 357 specifically because they depend on the stable voltage silver oxide provides.

How alkaline and silver oxide batteries differ

An LR44 alkaline battery uses zinc and manganese dioxide as its chemical pair. As it discharges, the voltage it delivers drops gradually — it starts at 1.5 volts and falls to around 0.9 volts by the time it is depleted. This slow voltage decline is usually not a problem for straightforward devices, but it can cause a watch to slow down or a toy to dim before the battery is completely dead.

A 357 silver oxide battery uses silver oxide and zinc. It maintains a much steadier voltage throughout its life — it stays close to 1.55 volts for most of its discharge cycle, then drops off sharply at the very end. This flat voltage curve means a device powered by a 357 will work at full strength until the battery is nearly exhausted, then stop suddenly rather than gradually weakening.

Because of this difference, a 357 typically lasts two to three times longer than an LR44 in the same device. The trade-off is cost: a 357 usually runs two to four times the price of an LR44, depending on the brand and where you buy it.

When to use LR44 instead of 357

An LR44 is the right choice for devices that do not demand stable voltage and where battery life is not critical. Calculators, basic digital thermometers, small LED flashlights, and many toys work perfectly well on LR44 batteries. If the device is used only occasionally or you do not mind replacing the battery every few months, the lower cost of an LR44 makes sense.

Devices that came with an LR44 from the factory were designed with that battery's voltage curve in mind. The manufacturer tested the device with an LR44 and set the circuit to work within those parameters. Swapping in a 357 will not damage anything, but it is not necessary and wastes money.

When a 357 is the better choice

If your device originally came with a 357, you should replace it with another 357. This is especially true for watches, hearing aids, and light meters — devices where consistent voltage matters. A watch powered by an LR44 will gradually slow down as the battery weakens, and you may not notice until it is significantly off time. A hearing aid powered by an LR44 will gradually lose volume. A light meter will give increasingly inaccurate readings.

Precision instruments like multimeters and some medical devices also specify a 357 because they depend on that stable voltage to give correct measurements. If the manual says 357, use a 357. If the manual says LR44, an LR44 is fine, though a 357 will work and last longer if you are willing to pay for it.

What happens if you mix them up

Putting an LR44 into a device designed for a 357 will usually work at first, but the device may behave oddly as the battery weakens. A watch will slow down. A hearing aid will fade. A light meter will drift. The device will not break, and you can use it in an emergency, but performance will degrade before the battery is truly dead.

Putting a 357 into a device designed for an LR44 is harmless. The device will work normally, and the battery will last longer. You are straightforward overpowering the device with a better battery, which causes no harm. The only downside is that you paid more than you needed to.

Other button cell batteries that look the same

LR44 and 357 are not the only button cells that share the same physical size. You may also encounter AG13, SR44, and SR44W batteries, all of which fit the same slot. AG13 is another name for an LR44 (different manufacturers use different codes). SR44 and SR44W are silver oxide batteries similar to a 357, with SR44W being a slightly higher-capacity variant.

The safest approach is to check what battery your device originally came with or what the manual specifies. If you cannot find that information, look at the battery compartment — sometimes the correct battery type is printed inside the cover. When in doubt, an LR44 is the cheaper experiment, and if it does not work well, you can always swap it for a 357.

How to identify which battery you have

The battery type is printed on the flat top surface of the cell. An LR44 will say "LR44" or "AG13". A 357 will say "357" or "SR44" (or SR44W). If the printing is worn off, you can tell them apart by weight — a 357 is noticeably heavier because silver oxide is denser than the alkaline chemistry inside an LR44. You can also test voltage with a multimeter: an LR44 fresh from the package reads around 1.5 volts, while a 357 reads around 1.55 volts.

When you buy replacement batteries, the package will clearly state which type you are getting. Buy the type that matches your device, or buy an LR44 if you are unsure — it is the cheaper option to test with.

Frequently Asked Questions

Can I use a 357 battery in a device that came with an LR44?

Yes, a 357 will work in any device designed for an LR44. The battery will fit, and the device will function normally. The 357 will last longer, but it costs more, so there is no practical reason to swap unless you want the longer lifespan.

Will an LR44 damage my device if I use it instead of a 357?

No, an LR44 will not damage your device. However, if your device was designed for a 357 — especially a watch or hearing aid — it may not work as well. The device will gradually lose performance as the LR44 weakens, rather than working at full strength until the battery dies.

Why do batteries have so many different names for the same size?

Different manufacturers use different naming codes for the same physical battery. LR44 and AG13 are both alkaline button cells of the same size. SR44 and 357 are both silver oxide cells of the same size. The codes tell you the chemistry, not just the size, so the same physical slot can hold different battery types.

How do I know which battery my device originally used?

Check the manual or the battery compartment cover — the correct type is often printed there. If you have the original battery, the type is stamped on the flat top. If you cannot find that information, an LR44 is the safer choice to try first because it is cheaper.

Is a 357 battery worth the extra cost?

It depends on the device. For a watch or hearing aid, yes — the longer life and stable voltage are worth it. For a calculator or toy used occasionally, an LR44 is fine and saves money. If you use the device daily, a 357 will cost less over time because you replace it less often.