AA vs AAA battery
Both are 1.5V and use the same chemistry, but AA is wider and longer with roughly 2x the capacity of AAA.
Side-by-side specs
| Spec | AA | AAA |
|---|---|---|
| Diameter | 14.5 mm | 10.5 mm |
| Length | 50.5 mm | 44.5 mm |
| Voltage | 1.5V | 1.5V |
| Typical capacity | 2400–3000 mAh | 860–1200 mAh |
View on Amazon | View on Amazon
Can you substitute one for the other?
No. The diameter difference (4mm) means neither format physically fits in the other's tray. This is not a spring-clearance situation — the housing sizes are incompatible.
Physical size comparison (to scale)
Which devices take which
TV remotes, mice, and flashlights usually take AA for longer runtime. Slim remotes, small flashlights, and portable keyboards more often require AAA for their narrower profile.