CellChart
Comparison

LR43 vs SR43

The LR43 and SR43 are the same size of button cell, 11.6 mm across and 4.2 mm tall, so they interchange with no fitting question at all. The LR43 is 1.5 volt alkaline holding 80 to 120 mAh. The SR43, sold as the 386 or the 301, is 1.55 volt silver oxide holding 120 to 130.

LR43 and SR43 drawn side by side at the same scale: LR43 is 11.6 mm across, 4.2 mm thick; SR43 is 11.6 mm across, 4.2 mm thickLR43SR43 LR43 1.5V + ⌀ 11.6 mm 4.2 mm SR43 1.55V + ⌀ 11.6 mm 4.2 mm
LR43 vs SR43 at the same scale: both 11.6 mm across, 4.2 mm thick.
LR43SR43
ChemistryAlkaline (Zn/MnO2)Silver oxide (Ag2O)
Voltage1.5 V1.55 V
Diameter11.6 mm11.6 mm
Height4.2 mm4.2 mm
Capacity80-120 mAh120-130 mAh
Also sold asAG12, LR1142, L1142, 186386, 301, SR1142, SR43W (386)

This size has an unusually grown-up device list for a button cell. Pocket calculators, medical thermometers, photographic equipment and vintage cameras all specified it, and at 120 to 130 mAh the silver version sits closer to a small battery than a watch cell. Meters and camera electronics are exactly the loads that reward a supply which does not sag.

That is the whole argument for the SR43. Silver oxide sits at 1.55 volts and stays within a hair of it until the cell is nearly finished, while alkaline opens at 1.5 and declines the entire way down. An instrument calibrated around a steady supply reads true on the first and drifts on the second, and it often flags a low battery while useful charge is still in the cell.

The names to recognise: alkaline is LR43, AG12, LR1142, L1142, 186 or V12GA, while silver is SR43, 386, 301 or SR1142, where the 386 is the high-drain SR43W and the 301 the low-drain SR43SW. Do not let the 11.6 mm diameter tempt you into grabbing an LR44 or a 357 instead. Those stand 5.4 mm tall and will not seat in a compartment built for 4.2.

All about LR43 All about SR43

Frequently asked questions

Is a 386 worth the extra over an AG12?
In a calculator, camera or medical instrument, yes. You get 120 to 130 mAh instead of 80 to 120, and a flat 1.55 volts instead of a slow decline from 1.5, which keeps meters and displays honest. In a toy, the alkaline AG12 is perfectly adequate and cheaper.
Can I use a 301 instead of a 386?
Yes. Both are SR43 silver-oxide cells at 11.6 by 4.2 mm and 1.55 volts, and they fit the same compartment. The 386 is the high-drain SR43W, the 301 the low-drain SR43SW meant for simple analog watches. Matching the drain type to the device gets the best life.
Why does my old camera meter read oddly on an LR43?
Because the meter circuit assumes a fixed supply voltage. An alkaline LR43 starts at 1.5 volts and falls steadily as it drains, so readings shift across the battery's life. A silver-oxide 386 holds 1.55 volts nearly to the end, which keeps those readings consistent from new to flat.

⚠️ Keep away from children. Swallowed button batteries, especially 20 mm lithium coins, cause severe injury within hours. If a child swallows one, call the 24/7 National Battery Ingestion Hotline (US) at 800-498-8666 or poison control at 800-222-1222 immediately. What every parent should know.