1. They’re all 1.5 volts
The AA, the AAAA and the N are the same voltage and the same chemistry. The difference is size: the AA is the biggest, the AAAA is the slimmest, and the N is the shortest.
2. The AA is the standard
At 50.5 mm long and 14.5 mm wide, the AA is the one you see everywhere: TV remotes, clocks, flashlights, toys and camera flashes. It also holds the most energy, so it lasts longest.
3. The AAAA is the slim one
The AAAA is 42.5 mm long and 8.3 mm wide, roughly the length of your little finger. It fits wireless mice, small game controllers and slim Bluetooth accessories.
4. The N is the short one
The N is 30.2 mm long but 12 mm wide, so it’s stubby rather than slim. You’ll find it in small remote controls, sensors and some toys.
5. They don’t interchange
An N is too short for an AAAA slot, and an AAAA is too thick for an N slot. Forcing the wrong one in can crush it or stop the contacts closing properly.
6. Match the mark in the device
The battery compartment is usually stamped with the size, such as AA or LR6. Look there first, and check the old battery if the printing is still readable.