Index / Shells / 11.6 x 4.2 mm
11.6 x 4.2 mm
5 designations carry this exact envelope and they disagree on voltage: MR43 runs 1.4 V where SR43 runs 1.55 V, 9.7% apart. The compartment cannot tell them apart and the circuit can. Capacity is where they part: SR43 holds 110 mAh and MR43 holds 160, 1.5 times as much. This envelope has no household name, so the code on the cell is the only handle on it.
Every cell in this shell at one scale
| Cell | Envelope | Volts | Chemistry | Energizer |
|---|---|---|---|---|
| LR43 | 11.6 x 4.2 mm | 1.5 V | alkaline | Listed |
| SR43 | 11.6 x 4.2 mm | 1.55 V | silver oxide | Listed |
| MR43 | 11.6 x 4.2 mm | 1.4 V | mercuric oxide | Not listed |
| NR43 | 11.6 x 4.2 mm | 1.4 V | mercuric oxide | Not listed |
| PR43 | 11.6 x 4.2 mm | 1.4 V | zinc air | Not listed |
Also stamped on cells in this table: LR43, 186, SR43, 1132SO, 301, 1133SO, 386, 1133SO/1132SO, 386/301, 1183SO, S41E, MR43, 1153M, 354, NR43, 1182M, E41E, PR43, 7001Z, AC41E.
What is gone from this shell
3 designations of the 5 here are no longer listed by Energizer: MR43, NR43 and PR43. The table below measures each still-listed cell against MR43; the others carry their own figures on their own pages.
Fit answers whether it enters the compartment; every cell here shares the envelope, so fit is already settled. Voltage answers whether the circuit will notice, and chemistry answers what the voltage column cannot say. A cell that fits is not always a safe substitute.
| Still listed | Voltage against MR43 | What the percentage does not say |
|---|---|---|
| LR43 | 1.5 V +7.1%reads off | Alkaline rather than mercuric oxide, so it empties along a different curve |
| SR43 | 1.55 V +10.7%reads off | Silver oxide rather than mercuric oxide, so it empties along a different curve |
Before you swap anything
Everything here is computed from published dimensions and nominal voltages. That answers whether a cell enters the compartment and whether the voltage matches on paper. It does not answer what your device does with the difference, and it cannot: a cell that fits can still be the wrong cell.
One more limit, and it is the biggest. This site reads a single manufacturer’s catalog. When a page says a designation is not listed, that means Energizer no longer offers a part under it — not that nobody makes the cell. Other makers may still sell it, and for common sizes they usually do.
A voltage difference is one relation between two cells, and this page prints it from the cell it is about — in every table on the page, including the one listing cells no longer made. A figure always belongs to the cell whose voltage is printed beside it: a cell that runs lower than this one carries a minus here, one that runs higher carries a plus, and two cells at the same nominal voltage carry zero. Meet the same pair on the other cell’s page and the sign is the other one, with the figure taken against that cell instead of this one; where the two run at the same voltage, both pages print zero. The class beside the figure is not read off that figure directly. It is decided on the gap itself, taken against the higher of the two nominal voltages, so one pair of cells gets one class whichever page you meet it on: counted from this side the boundary of the class that still runs falls at 20.0% below and 25.0% above, which is the same gap divided once by the larger nominal and once by the smaller. What genuinely differs between the two directions is the consequence, and the words carry it: a cell that runs low makes a calibrated instrument read below true, and a cell that runs high makes it read above.
3 things this site cannot see. Whether the contacts reach a shorter cell. Whether the device was calibrated for a chemistry that holds its voltage flat, which silver oxide does and alkaline does not. Whether the equipment tolerates the higher current a different chemistry can deliver. Rechargeable cells are never a drop-in for primary cells regardless of size.