The LR43 is a small 1.5-volt alkaline button battery, about 11.6 mm wide and 4.2 mm thick. Its exact equivalents are the 186 and the AG12: Energizer’s 186 battery is an IEC LR43 alkaline cell. The silver oxide version of the same size is sold as 386 or 301 (IEC SR43), and it gives 1.55 volts.
This guide uses Energizer’s own data sheets and its battery cross-reference guide. It compares the alkaline LR43 with its silver oxide twins, explains how it differs from the LR44 and LR1130, and shows which one to buy.
| LR43 / 186 / AG12 (alkaline) | 386 / 301 / SR43 (silver oxide) | |
|---|---|---|
| Diameter | 11.30-11.60 mm | 11.30-11.60 mm |
| Height | 3.80-4.20 mm | 3.80-4.20 mm |
| Nominal voltage | 1.5 V | 1.55 V |
| Typical capacity | 123 mAh (to 0.9 V) | 120 mAh (386, to 1.3 V) |
| Weight | 1.5 g | 1.7 g |
| IEC code | LR43 | SR43 |
| US (ANSI/NEDA) code | – | 1133SO (386), 1132SO (301) |
What is the equivalent of an LR43 battery?
Exact alkaline equivalents: 186 and AG12. Energizer sells its alkaline cell of this size as the 186, and its data sheet gives the IEC name LR43.
Silver oxide versions of the same size: 386 and 301, also sold as SR43 or SR43W. Energizer’s cross-reference guide lists one 386/301 cell size that replaces batteries labelled 386, 301, SR43W, SG12, 260, 226, 186, LR43 and AG12, among other names.
All of these names fit the same battery slot. The difference is the chemistry inside: alkaline (the “L” codes) or silver oxide (the “S” codes).
Can I use a 386 instead of an LR43?
Yes. A 386 is the same size as an LR43 and gives a very close voltage (1.55 V against 1.5 V). Energizer’s silver oxide manual says silver oxide cells have a flatter discharge curve than alkaline ones, so a 386 holds its voltage more steadily as it runs down. That suits watches and medical or measuring devices.
The alkaline LR43 is usually the cheaper choice and is fine for toys and simple gadgets.
386 vs 301: what is the difference?
Both are silver oxide SR43 cells of the same size. Energizer gives them different US codes (1133SO and 1132SO):
- 386: the data sheet says it is designed for continuous low drain plus high pulse drain on demand, like a watch with a light or alarm.
- 301: the data sheet says continuous low drain only. Energizer’s current 301 sheet is marked obsolete, and its cross-reference guide sells the size as one 386/301 cell.
If your old battery says 301, a 386 is a safe replacement.
LR43 vs 386: voltage as the battery drains
Energizer’s data sheets show how the voltage falls as each battery is used up, measured on a short pulse with a 100-ohm load at 21°C (70°F):
- 186 (alkaline LR43): about 1.52 V when new, 1.19 V at 40% used and 1.07 V at 80% used.
- 386 (silver oxide): about 1.45 V when new, 1.36 V at 40% used and 1.28 V at 80% used.
The silver oxide cell drops much less. A device that needs a steady voltage may stop working before an alkaline cell is fully used.
Is LR43 the same as LR44?
No. They are the same width, but an LR44 is thicker: up to 5.40 mm, against 4.20 mm for the LR43 in Energizer’s data sheets. An LR44 will not fit an LR43 slot. An LR43 in an LR44 slot will be loose and may not touch the contacts, so don’t swap them.
The LR1130 (189) is the same width again, but thinner: up to 3.05 mm. So the three sizes stack up like this: LR1130 is the thinnest, then LR43, then LR44.
What does LR43 mean?
- L: alkaline chemistry (as in LR44 and LR41)
- R: round
- 43: the IEC size code, which the silver oxide SR43 shares
Numbers like 186, 386 and 301, and names like AG12, are maker and retail codes for the same size.
Where LR43 batteries are used
Energizer’s cross-reference guide lists watches, medical devices and sporting goods as common uses for its 386/301 size. Always check the code on the old battery or in the manual before you buy, because many button cells look alike.
Button battery safety
Small button batteries are dangerous if swallowed. Keep new and used cells away from children and pets. If you think a child has swallowed one, get emergency medical help straight away.
Related battery guides: LR44 vs 357 vs AG13 vs SR44, LR1130 battery equivalents, LR41 battery equivalents and SR626SW and 377 equivalents.
Frequently asked questions
Is LR43 the same as 186?
Yes. Energizer’s 186 is an alkaline LR43 cell, so the two names mean the same battery.
Is AG12 the same as LR43?
Yes. AG12 is a common name for the alkaline LR43 size. Energizer’s cross-reference guide lists AG12 next to 186 and LR43.
Is LR43 the same as 386?
Same size, different chemistry. The 386 is a silver oxide SR43 (1.55 V). The LR43 is alkaline (1.5 V). A 386 works in place of an LR43.
Can I use LR44 instead of LR43?
No. The LR44 is the same width but about 1.2 mm thicker, so it won’t fit an LR43 slot.
What size is an LR43 battery?
About 11.6 mm (0.46 in) across and 4.2 mm (0.17 in) thick. Energizer’s 186 data sheet gives 11.30-11.60 mm by 3.80-4.20 mm.
What voltage is an LR43?
1.5 volts nominal. Silver oxide 386 and 301 cells of the same size are 1.55 volts.
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