357 and LR44 batteries are not identical, but they are often interchangeable

A 357 battery and an LR44 battery have the same voltage (1.5 volts) and nearly identical physical dimensions, so they will fit in the same device and work in most cases. However, they are not made from the same chemistry. A 357 is a silver oxide battery, while an LR44 is an alkaline battery. This difference matters for how long each one lasts and how much power it delivers over time.

The 357 will typically outlast an LR44 in the same device because silver oxide batteries maintain their voltage more consistently as they drain. An LR44 will work as a substitute for a 357, but it may run out of power sooner. If your device manual specifies one type, that is the better choice — but in a pinch, either will usually function.

Key Takeaways

  • A 357 is silver oxide chemistry and an LR44 is alkaline chemistry, so they perform differently even though they have the same voltage and fit the same space.
  • The 357 holds its voltage longer as it drains, making it last longer in devices that draw steady power, like watches and hearing aids.
  • An LR44 will work in a device designed for a 357, but it will drain faster and may not power the device for as long.
  • A 357 costs more per battery than an LR44, so cost and expected device lifespan should both factor into which one you choose.

Why the chemistry difference matters for runtime

Silver oxide batteries like the 357 deliver power at a steady rate throughout their life. This means a watch or hearing aid powered by a 357 will run at full strength until the battery is nearly dead. Alkaline batteries like the LR44 lose voltage gradually as they drain, so the device may slow down or dim before the battery is completely empty.

For devices that are sensitive to voltage drop — such as hearing aids, watches, and light meters — the 357 is the better choice because the device will work reliably until the battery fails. For devices that tolerate a gradual power loss, like some calculators or toys, an LR44 is often sufficient and costs less.

Physical size and fit

Both batteries measure 11.6 millimeters in diameter and 5.4 millimeters in thickness. They are both button cell batteries, and they will physically fit into any device designed for either one. The battery compartment does not care about chemistry — it only cares about size and voltage. This is why they are often listed as interchangeable on product pages and battery charts.

However, physical fit is not the same as optimal performance. Just because a battery fits does not mean it will power the device for the same length of time or with the same reliability.

Cost and availability

LR44 batteries are cheaper and easier to find because alkaline chemistry is more common and less expensive to manufacture. You can buy a pack of LR44s at most drugstores, supermarkets, and online retailers for roughly half the price of a 357. A 357 is more specialized and may require a trip to a watch repair shop, hearing aid center, or online battery seller.

If you use button cell batteries regularly, buying in bulk online is usually the cheapest route for either type. Prices vary by brand and quantity, so comparing a few sellers before ordering a large pack will save money over time.

When to use a 357 instead of an LR44

Use a 357 if your device is a hearing aid, watch, light meter, or any precision instrument where consistent voltage is critical. These devices are designed around the 357's steady power curve, and substituting an LR44 may cause the device to malfunction or shut off unexpectedly. Hearing aids in particular are engineered for the 357's performance profile, and using an LR44 can result in poor sound quality or frequent battery changes.

If the device manual or the battery compartment lid specifies a 357, that is the battery the manufacturer tested and approved. Using it ensures the device will perform as intended.

When an LR44 is acceptable as a substitute

An LR44 will work in most toys, calculators, small flashlights, and other low-power devices that originally called for a 357. These devices are less sensitive to voltage drop, so the gradual power loss of an alkaline battery is not a problem. You will straightforward need to replace the LR44 more often than you would a 357.

If you are in a situation where a 357 is not available and you need the device to work when ready, an LR44 is a reasonable temporary solution. Just plan to buy the correct battery type for the next replacement.

How to tell which battery your device needs

Check the battery compartment lid or the device manual first. Most manufacturers print the battery type directly on the lid or in the instructions. If that information is not available, look up the device model number online — the product page or manual will specify the correct battery.

If you are still unsure, contact the manufacturer or a retailer that specializes in that type of device. A hearing aid center can tell you what battery a hearing aid needs. A watch repair shop can tell you what battery a watch needs. Guessing wrong wastes money and may damage the device.

Frequently Asked Questions

Can I use a 357 in a device that calls for an LR44?

Yes. The 357 will fit and work, and it will actually last longer because of its superior voltage stability. There is no downside to using a 357 in place of an LR44 except the higher cost per battery.

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

It will not damage the hearing aid, but it will not perform as well. The hearing aid may shut off unexpectedly as the LR44's voltage drops, or the sound quality may degrade. Hearing aids are designed for the 357's consistent power delivery, so using an LR44 is not recommended.

Are there other battery types that fit in a 357 or LR44 slot?

Yes. The SR44, which is also silver oxide, and the A76, which is alkaline, are both the same size and voltage. The SR44 performs similarly to the 357, while the A76 performs similarly to the LR44. Check your device manual to see which types are approved.

How long does a 357 battery last compared to an LR44?

Runtime depends on the device and how much power it draws. In a watch, a 357 typically lasts one to three years, while an LR44 may last six months to a year. In a hearing aid, a 357 may last three to seven days, while an LR44 may last one to three days. Check the device manual for expected battery life.

Can I store 357 and LR44 batteries together?

Yes. Both are stable at room temperature and do not interact with each other. Store them in a cool, dry place away from metal objects that could short-circuit them. Keep them in their original packaging or a battery organizer to prevent accidental discharge.