Short answer
If the pack or device says LR44, AG13, A76, L1154, LR1154, GPA76, PX76A, V13GA, G13A or 1166A, you want the same alkaline button cell — about 11.6 × 5.4 mm and 1.5 V.
If it says SR44, 357, 303 or SR44SW, that is silver oxide at the same size — not an automatic LR44 swap.
Same battery (alkaline LR44 family)
IEC-style code: LR44. Retail and brand packs often print AG13 or A76 instead. L1154 / LR1154 are the same size family on many blister packs.
These are labelling differences, not different diameters. Buying “AG13” when the tray says LR44 is normal.
Same size, different chemistry (do not auto-swap)
SR44 (often sold as 357 or 303) fits the same tray but uses silver-oxide chemistry (~1.55 V). Watches, calipers and meters that name silver oxide may misbehave on alkaline.
Only use SR44 / 357 when the device or empty pack names that chemistry — not because “it fits.”
How to decide quickly
Read the empty pack or the device page first. Match chemistry (alkaline vs silver oxide), then size.
Use the pack-label checker if the blister code is unfamiliar. Open the LR44 or SR44 battery page for devices we have already verified.