Watch Battery Size Cross Reference / Equivalent Chart

The SR626SW battery is equivalent to the Energizer 377, Duracell D377, Renata 37, Seiko SB-AW, Timex BA, Maxell SR626SW, and Varta V377. All of these are 1.55V silver oxide batteries measuring 6.80mm in diameter and 2.60mm in height. The SR626SW is one of the most common watch batteries used in analog quartz watches.

While alkaline (LR) and silver oxide (SR) watch batteries may share the same physical dimensions, they are not ideal substitutes. Silver oxide batteries maintain a stable 1.55V output throughout their life, which is critical for accurate timekeeping in quartz watches. Alkaline batteries start at 1.5V and gradually decline, which can cause your watch to lose time or stop prematurely. For watches, always use the silver oxide (SR) version when specified.

Watch battery names follow the IEC naming convention. The first two letters indicate the chemistry: SR means Silver Oxide (1.55V), LR means Alkaline (1.5V), and CR means Lithium (3.0V). The numbers that follow indicate the physical dimensions: the first two digits represent the diameter in millimeters (multiplied by 10), and the last two digits represent the height. The suffix SW means "low drain" (standard watches), while W means "high drain" (watches with backlights or alarms). For example, SR626SW is a Silver oxide battery, 6.8mm diameter, 2.6mm height, low drain.

There are three reliable methods to find the correct replacement watch battery. First, check the back of your current battery for a printed model number (e.g., SR626SW, 377, or V377) and look it up in the cross-reference chart above. Second, if the number is worn off, measure the battery diameter and height with calipers or a micrometer and match it to the dimensions column. Third, consult your watch manufacturer’s manual, which typically lists the recommended battery model. Any equivalent listed in the same row of the cross-reference chart will work as a direct replacement.

A 377 and SR626SW are the exact same battery. The number 377 is the Energizer/Eveready/Rayovac designation, while SR626SW is the IEC (International Electrotechnical Commission) standard name. Other equivalent names for this same battery include Maxell SR626SW, Duracell D377, Renata 37, Seiko SB-AW, and Varta V377. They are all 1.55V silver oxide button cells measuring 6.80mm x 2.60mm.

Silver oxide watch batteries typically last between 1 and 3 years in a standard analog quartz watch, depending on the watch movement’s power consumption and the battery capacity. Larger batteries (like the 357/SR44 at 11.6mm diameter) generally last longer than smaller ones (like the 317/SR516SW at 5.8mm diameter) because they have higher milliamp-hour (mAh) capacity. Digital watches, chronographs, and watches with backlights drain batteries faster. Silver oxide batteries have an excellent shelf life of 3 to 5 years when stored in a cool, dry place.

The most common watch battery sizes are the 377 (SR626SW), 371 (SR920SW), 364 (SR621SW), and 379 (SR521SW). The 377/SR626SW is by far the most widely used, found in the majority of standard analog quartz watches from brands like Timex, Casio, Fossil, and Seiko. If you are stocking up on watch batteries, these four sizes will cover the vast majority of watches.

No, not all watch batteries are 1.5 volts. Silver oxide watch batteries (SR series) output 1.55V, alkaline watch batteries (LR series) output 1.5V, and lithium coin cell batteries (CR series like CR2032) output 3.0V. It is important to match the correct voltage when replacing a watch battery. Using a 3V lithium battery in place of a 1.55V silver oxide battery can damage your watch movement. Always check the cross-reference chart to ensure you are selecting the correct chemistry and voltage.

Low-drain (SW) batteries use a sodium hydroxide electrolyte and are optimized for standard analog watches that only move hands. High-drain (W) batteries use a potassium hydroxide electrolyte, offering lower internal resistance to handle sudden bursts of power from features like backlights, alarms, and chronographs. Both versions share the same physical dimensions and 1.55V output, the only difference is the internal electrolyte chemistry that determines how quickly the battery can deliver energy.

Yes, a high-drain battery can be used in a low-drain watch without harming the movement. The watch will only draw the current it needs. However, the high-drain battery may have a slightly higher self-discharge rate, meaning it could potentially run out a few months sooner than a dedicated low-drain (SW) version in a simple analog watch.

The watch may keep time normally, but it will likely fail, reset, or dim the moment you try to use a power-hungry feature like a backlight, alarm, or chronograph. The low-drain battery simply cannot push out energy fast enough to satisfy those high-demand components. For watches with features beyond basic timekeeping, always use a high-drain (W) or Multi-Drain battery.

Look at your watch’s features. If it has a digital display, LED light, loud alarm, beeper, or stopwatch, it is likely a high-drain device and needs a W or Multi-Drain battery. If it simply tells the time with analog hands and perhaps a date window, it is a low-drain watch and an SW battery is the standard choice. When in doubt, a Multi-Drain battery is the safest option because it works in both types of watches.

Multi-Drain batteries are a modern design that combines the low self-discharge of SW (low-drain) batteries with the high pulse capability of W (high-drain) batteries. Major brands like Renata, Energizer, and Duracell now produce Multi-Drain cells, meaning one battery model can safely replace both the W and SW versions. For example, a Renata 371 is a Multi-Drain cell that replaces both the 371 (low-drain) and 370 (high-drain). If you can only find one version of a battery size, it is almost certainly a Multi-Drain cell that will work in any watch.