Index / LR41 / LR41 vs SR41

LR41 vs SR41: what differs, and which goes where

LR41 and SR41 share the same 7.9 x 3.6 mm envelope. LR41 is an alkaline cell at 1.5 V; SR41 is a silver oxide cell at 1.55 V. SR41 in a holder built for LR41: drop-in, at 1.55 V against 1.5 V. LR41 in a holder built for SR41: drop-in, at 1.5 V against 1.55 V.

Warning — button cell

LR41 is a button cell: 7.9 mm across and 3.6 mm tall. If one has been swallowed, or put in a nose or an ear, call the United States national Poison Help line at 1-800-222-1222 straight away and do not wait for symptoms.

Why this shape is dangerous, and the law behind the pack

United States law defines that class by the shape alone — a single cell battery with a diameter greater than its height, 16 CFR 1263.2 — and not by what is inside it. Swallowed, a cell this shape can lodge instead of passing, and it is the current, not the metal, that does the damage.

At 7.9 mm and 1.5 V it is under the 16 mm diameter that lodges most readily — which makes it easier to swallow, not safer. The same current runs for as long as it sits.
Reese's Law (15 U.S.C. 2056e) and 16 CFR part 1263 put child-resistant packaging and a warning label on this class; packages manufactured or imported after 21 September 2024 carry it. That is why the pack is hard to open.
The same rule says what to do with the used cell, in its own words: dispose of it at once, keep it away from children, and do NOT put it in household trash (16 CFR 1263.4(b)(3)). Tape over both faces first — a cell too flat to run a watch still has enough left to burn.

Side by side

Every figure below is published by the maker for LR41 and SR41; the last column is ours, the difference read off the printed tenths of a millimeter.

LR41 and SR41, published figures
Figure	LR41	SR41	Difference
Diameter	7.9 mm	7.9 mm	same
Height	3.6 mm	3.6 mm	same
Nominal voltage	1.5 V	1.55 V	close enough
Chemistry	alkaline	silver oxide	different
Capacity	45 mAh	41 mAh	—
Stored energy	68 mWh	64 mWh	—
In the Energizer catalog	not listed	listed	—
Sold as	LR41, AG3, 192, 192Z	SR41, 392, SG3, SR736SW, SR736W, 1134SO, 384	—

Either way round

Fit and voltage are separate answers, and they change with direction: the holder is built for one cell, and the other has to live with it. LR41 is 3.6 mm deep and SR41 is 3.6 mm.

SR41 in a holder built for LR41 — SR41 matches the holder within 0.3 mm; it runs 1.55 V against the 1.5 V the device expects, a few hundredths of a volt above, which almost nothing notices.
LR41 in a holder built for SR41 — LR41 matches the holder within 0.3 mm; it runs 1.5 V against the 1.55 V the device expects, a few hundredths of a volt below, which almost nothing notices.

From BatteryCrossEvery designation in one pageEach code with what it measures and what it replaces

Drawn to scale

Both at one scale. The dashed line marks the height of SR41: both reach it.

This cellAnother cell, same scale

How long each one runs

LR41 holds 45 mAh at 1.5 V, about 68 milliwatt-hours; SR41 holds 41 mAh, about 64. In the same device LR41 runs only slightly longer, 1.06 times, which is the whole reason the bigger cell exists. Price follows less closely than energy does. Per cubic centimeter LR41 packs 338 milliwatt-hours against 353 for SR41, so the difference is chemistry and construction, not only size.

What each one is made for

Both are made for watches, calculators and small instruments that draw very little, which is why they end up in the same drawer and get mixed up: LR41 at 1.5 V and SR41 at 1.55 V. Read the code off the old cell before buying: the device was designed around that one, and the drawing above is how the other one sits in it.

Alkaline (LR41, 1.5 V) drops in voltage steadily as it empties, so a device calibrated for a flat discharge will drift as it goes.
Silver oxide (SR41, 1.55 V) holds its voltage almost flat until it is spent, which is why watches and light meters were built around it.

What the codes and the sheets add

LR41 does not encode its size, so only the sheet says it; SR41 does not encode its size, so only the sheet says it. Beyond size and voltage, the sheets say this: LR41 weighs 0.6 g and SR41 weighs 0.6 g.

Telling them apart in the hand

The code is printed on the flat face of each: LR41 on one, SR41 on the other. On a caliper they read the same within 0.3 mm, so the printed code and the chemistry on the label are the only things that separate them. If the old cell is gone and the code with it, measure the holder instead: its depth and its opening are what this page compares.

Names on the package

LR41 also appears as 192 and 192Z in Energizer's own part numbers, and other brands sell it as AG3; SR41 also appears as 1134SO, 384 and 1135SO/1134SO in Energizer's own part numbers, and other brands sell it as 392, SG3 and SR736SW. Energizer lists only SR41, which says what is on the shelf under these numbers and nothing about who else still makes them.

Which one to buy

Buy the code printed on the old cell or named in the manual. In a pinch SR41 can stand in where LR41 sat, at 1.55 V against 1.5 V. In a pinch LR41 can stand in where SR41 sat, at 1.5 V against 1.55 V. Both pages carry the full figures and sources: LR41 and SR41.

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.

Where these numbers come from

Dimensions, voltages, chemistries and capacities are published by the manufacturer and reproduced without change. Everything else on the page is ours, computed from those figures: whether one cell fits where another sat, how far apart their voltages are, stored energy and energy per cubic centimeter, the rank within a shell, and the check of the designation against the measured size.

Fit is decided within 0.3 mm on every axis, which is the order of a contact spring's travel. Voltage classes are decided by consequence, not by roundness, and they are decided on the gap between two nominal voltages taken against the higher of the two: 2.0% or less of it is the same working voltage, 6.0% starts to matter to a calibrated instrument, and past 20.0% it is a different class altogether. Measuring the gap against the higher figure is what makes the verdict the same from either cell’s page, while the printed percentage stays counted from the cell you are reading about. Cells with identical stored energy share a rank instead of being ordered arbitrarily.

Ranking uses capacity times nominal voltage, because capacity alone is not comparable across chemistries: 150 mAh at 3 V is twice the energy of 150 mAh at 1.5 V. Neighbors are chosen by measurement and never alphabetically, because two cells filed next to each other by name usually have nothing in common. A blank in any table means the maker publishes no figure, which is not the same as zero.

Source: Energizer technical data, retrieved 1 September 2026.