LR44 vs SR44
The LR44 and SR44 are the same size of button cell, 11.6 mm across and 5.4 mm tall, and they fit the same devices. The LR44 is alkaline at 1.5 volts with 110 to 130 mAh; the SR44 is silver oxide at 1.55 volts with 150 to 200 mAh and a far steadier discharge.
| LR44 | SR44 | |
|---|---|---|
| Chemistry | Alkaline (Zn/MnO2) | Silver oxide (Ag2O) |
| Voltage | 1.5 V | 1.55 V |
| Diameter | 11.6 mm | 11.6 mm |
| Height | 5.4 mm | 5.4 mm |
| Capacity | 110-130 mAh | 150-200 mAh |
| Also sold as | AG13, A76, L1154, LR1154 | 357, 303, SR1154, SR44W (357) |
Interchangeability is not the question here; the two swap without any fitting issues. The question is behavior over the battery's life. An alkaline LR44 starts at 1.5 volts and declines steadily, passing through 1.3, 1.2 and onward as it drains. A silver-oxide SR44 holds within a few hundredths of 1.55 volts until it is nearly exhausted, then falls off a cliff.
That discharge curve decides which chemistry belongs in which device. Digital calipers, light meters, watches and medical instruments read voltage-sensitive circuits; on a sagging alkaline they show low-battery warnings early, drift out of accuracy, or die with capacity still in the cell. On silver oxide they simply work until the end. Toys, laser pointers and party gadgets do not care, and for them the LR44's lower price wins.
Cost per use usually favors the SR44 too. It typically costs two or three times as much per cell but delivers up to double the capacity plus full usability of that capacity, so devices that matter go through fewer batteries and fewer failures. Buy LR44 multipacks for the junk drawer and a branded 357 (the SR44's retail number) for the instruments.