LR44 vs SR44: what differs, and which goes where
LR44 and SR44 share the same 11.6 x 5.4 mm envelope. LR44 is an alkaline cell at 1.5 V; SR44 is a silver oxide cell at 1.55 V. SR44 in a holder built for LR44: drop-in, at 1.55 V against 1.5 V. LR44 in a holder built for SR44: drop-in, at 1.5 V against 1.55 V.
Side by side
Every figure below is published by the maker for LR44 and SR44; the last column is ours, the difference read off the printed tenths of a millimeter.
| Figure | LR44 | SR44 | Difference |
|---|---|---|---|
| Diameter | 11.6 mm | 11.6 mm | same |
| Height | 5.4 mm | 5.4 mm | same |
| Nominal voltage | 1.5 V | 1.55 V | close enough |
| Chemistry | alkaline | silver oxide | different |
| Capacity | 150 mAh | 138–200 mAh | — |
| Stored energy | 225 mWh | 297 mWh | — |
| In the Energizer catalog | listed | listed | — |
| Sold as | LR44, AG13, A76, 76A, GP76A, 1166A | SR44, 357, SG13, V357, SR1154SW, 1131SO | — |
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. LR44 is 5.4 mm deep and SR44 is 5.4 mm.
- SR44 in a holder built for LR44 — SR44 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.
- LR44 in a holder built for SR44 — LR44 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.
Drawn to scale
Both at one scale. The dashed line marks the height of SR44: both reach it.
How long each one runs
LR44 holds 150 mAh at 1.5 V, about 225 milliwatt-hours; SR44 holds 138–200 mAh, about 214–310. The data sheets behind SR44 print a range, and the ranges overlap, so which one runs longer depends on which product is in hand. Price follows less closely than energy does. Per cubic centimeter LR44 packs 395 milliwatt-hours against 375–544 for SR44, 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: LR44 at 1.5 V and SR44 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 (LR44, 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 (SR44, 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
LR44 does not encode its size, so only the sheet says it; SR44 does not encode its size, so only the sheet says it. Beyond size and voltage, the sheets say this: LR44 weighs 2 g and SR44 weighs 2.3 g.
Telling them apart in the hand
The code is printed on the flat face of each: LR44 on one, SR44 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
LR44 also appears as 1166A and A76 in Energizer's own part numbers, and other brands sell it as AG13, A76 and 76A; SR44 also appears as 1131SO, 357 and 357/303 in Energizer's own part numbers, and other brands sell it as 357, SG13 and V357. Energizer lists both, which says what is on the shelf under these numbers and nothing about who else still makes them.
Other comparisons: LR44 vs 675, LR43 vs LR44.
Which one to buy
Buy the code printed on the old cell or named in the manual. In a pinch SR44 can stand in where LR44 sat, at 1.55 V against 1.5 V. In a pinch LR44 can stand in where SR44 sat, at 1.5 V against 1.55 V. Both pages carry the full figures and sources: LR44 and SR44.
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 here is the figure for one swap: the voltage of the cell that goes in, measured against the cell the device was built for, and the figure belongs to the cell whose voltage is printed beside it. In the table of cells that fit in place of this one, and on the scale, that is each candidate against this cell: a cell that runs lower carries a minus, one that runs higher carries a plus, and a cell at the same nominal voltage carries zero. In the table of cells no longer made, it is this cell against each of them, because the swap goes into a device built for the old cell, and that cell’s own page prints the same figure for the same swap. Where cells still listed can each stand in for the other, those are different swaps: each page measures against its own cell, the sign is the other one, and the size can differ slightly, because one gap is a larger share of the lower voltage; 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.