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, which is why they work in many of the same devices. However, they are not chemically identical. A 357 is typically an alkaline battery, while an LR44 is also alkaline but may have slightly different internal chemistry depending on the manufacturer. In most household devices—watches, calculators, hearing aids, small electronics—you can swap one for the other without problems.

The real difference comes down to capacity and how long each battery lasts under load. A 357 generally holds a bit more charge than an LR44 in the same space, which means it may power a device slightly longer before dying. For low-drain devices like watches, you may not notice the difference. For higher-drain devices, the 357 might give you an extra week or two of use.

Before you swap them, check your device's manual or battery compartment label. Most manufacturers list both as acceptable, but some specify one or the other. If your device works with an LR44, a 357 will almost certainly work. The reverse is usually true as well, though less commonly tested by manufacturers.

Key Takeaways

  • Both 357 and LR44 batteries are 1.5 volts and fit the same battery compartments in most small electronics.
  • A 357 typically lasts slightly longer than an LR44 because it holds more charge, though the difference is often small in low-drain devices.
  • Check your device's manual or battery label to see which battery is recommended, though most devices accept both.
  • If your device works with an LR44, substituting a 357 is generally safe; the reverse swap is also usually safe but less commonly tested.

Why the names are different but the batteries look the same

The 357 and LR44 are named by different battery classification systems. The "357" comes from the International Electrotechnical Commission (IEC) standard, which uses a number-based code. The "LR44" comes from the IEC standard as well, but uses a letter-number format where "L" means alkaline and "R" indicates the cell shape and size. Both names refer to the same physical battery—a small, flat, round cell that is 11.6 millimeters in diameter and 5.4 millimeters thick.

Manufacturers often print both names on the same battery package to help consumers find what they need. You might see a battery labeled "357/LR44" or "LR44/357" on the packaging. This dual labeling exists because different regions and industries use different naming conventions, and retailers want to make sure customers can find the battery whether they search by one name or the other.

When a 357 lasts longer than an LR44

The capacity difference between a 357 and an LR44 becomes noticeable in devices that draw steady power over time. A 357 typically has a capacity of around 150 to 160 milliamp-hours (mAh), while an LR44 usually ranges from 100 to 150 mAh depending on the manufacturer. In a watch that draws very little current, this difference might mean the 357 lasts a few months longer. In a hearing aid or a glucose meter that draws more power, the difference could be several weeks.

The capacity difference also depends on the specific brand. Some LR44 batteries from premium manufacturers may perform as well as a 357 from a budget brand. Quality varies more between manufacturers than between the two battery types themselves. If you find that your device drains batteries quickly, switching to a 357 or trying a different brand may help, though the device itself may straightforward draw more power than the battery is designed for.

Devices where you can safely swap 357 and LR44 batteries

Watches are the most common place where these batteries are swapped. Both 357 and LR44 work in quartz watches, and the longer life of a 357 may mean fewer battery changes over the years. Calculators, small LED flashlights, and laser pointers all use these batteries interchangeably. Hearing aids, glucose meters, and blood pressure monitors also accept both, though you should check the device manual first because some hearing aid models specify one type.

Toys, remote controls, and small electronic games typically work with either battery as well. The key is that these are all low-drain or moderate-drain devices. If a device is designed to run for months or years on a single battery, it is almost certainly safe to swap. If you are unsure, look at the battery compartment label inside the device or consult the manual before making the change.

When you should not substitute one for the other

Some manufacturers test and certify their devices for one specific battery type and do not recommend substituting the other. This is rare, but it does happen. Always read the label inside the battery compartment or check the device manual before swapping. If the manual says "LR44 only" or "357 only," follow that instruction. The manufacturer may have tested the device with one battery and found that the other does not perform as expected, or they may have a supply chain reason for the specification.

Medical devices are the category where you should be most cautious. If your device is a hearing aid, pacemaker, or any implanted or critical medical device, use only the battery type specified by the manufacturer. The same applies to devices where battery failure could cause injury or data loss. For everything else—watches, calculators, toys—swapping is almost always safe.

How to tell which battery your device needs

Open the battery compartment of your device and look at the label printed inside. Most devices list the battery type clearly: "LR44," "357," or both. If both are listed, you can use either one. If only one is listed, use that one, though in practice the other usually works fine. Check the device manual as well—it often has a specifications section that lists the battery type.

If you have lost the manual and cannot read the label clearly, you can measure the battery compartment. Both 357 and LR44 batteries are 11.6 mm in diameter and 5.4 mm thick, so if your compartment fits one, it fits the other. You can also take a photo of the compartment label and search online for the device model number plus "battery type" to find the manual on the manufacturer's website.

Cost and where to find them

Both 357 and LR44 batteries are inexpensive and widely available. A single battery costs between 50 cents and 2 dollars depending on the brand and where you buy it. Bulk packs of 10 or more cost less per battery. You can find them at drugstores, supermarkets, hardware stores, and online retailers. Some brands are more reliable than others, but all major battery manufacturers make both types.

If you buy in bulk, store the batteries in a cool, dry place. Alkaline batteries last longer when kept at room temperature and away from moisture. Do not store them in the refrigerator, despite the old myth—cold storage does not extend alkaline battery life and can actually reduce performance. Check the expiration date on the package before buying, especially if you are purchasing from a store that may have old stock.

Frequently Asked Questions

Can I use a 357 in a device that says LR44?

Yes, in almost all cases. The 357 and LR44 are the same size and voltage, and the 357 often lasts longer. Check the device manual to be certain, but most manufacturers accept both. Medical devices and critical equipment are the exception—follow the label in those cases.

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

No. The 357 is the same voltage and size as the LR44, so it will not cause electrical damage. The worst that can happen is the battery lasts longer than expected, which is not a problem for most devices.

Why does my device manual list both 357 and LR44?

Manufacturers list both names because they are the same battery sold under different naming systems. Listing both helps customers find the battery whether they search by one name or the other. You only need to buy one type—they are interchangeable.

Is a 357 battery more expensive than an LR44?

No, they cost about the same. Price varies more by brand and retailer than by battery type. Buying in bulk usually saves money regardless of which type you choose.

How long does a 357 or LR44 battery last in a watch?

In a typical quartz watch, either battery lasts one to three years depending on the watch design and how often you use it. A 357 may last slightly longer, but the difference is usually just a few months. The battery life depends more on the watch than on which battery type you use.