AAA battery size
10.5 × 44.5 mm
1.5 V · Alkaline · Cylindrical · also sold as LR03, R03, MN2400, Micro
About the AAA
The small cylindrical cell in remotes, torches and computer mice. Its IEC name is LR03 for alkaline and R03 for zinc-carbon, and a rechargeable NiMH AAA is HR03 — same size, 1.2 volts rather than 1.5, which is why some devices dim on rechargeables and others do not care.
The numbers
| Diameter | 10.5 mm · 0.41 in |
| Height | 44.5 mm · 1.75 in |
| Nominal voltage | 1.5 V |
| Chemistry | Alkaline |
| Other names | LR03, R03, MN2400, Micro |
Same diameter, different length
These are the cells most often confused with a AAA, because they are exactly as wide and only differ in one dimension.
| Cell | Diameter | Length | vs AAA |
|---|---|---|---|
| A23 | 10.3 mm | 28.5 mm | -16.0 mm |
Other cylindrical sizes
| Cell | Size | Voltage |
|---|---|---|
| AA | 14.5 × 50.5 mm | 1.5 V |
| C | 26.2 × 50 mm | 1.5 V |
| D | 34.2 × 61.5 mm | 1.5 V |
| AAAA | 8.3 × 42.5 mm | 1.5 V |
| N | 12 × 30.2 mm | 1.5 V |
| A23 | 10.3 × 28.5 mm | 12 V |
| CR123A | 17 × 34.5 mm | 3 V |
| 18650 | 18 × 65 mm | 3.7 V |
| 21700 | 21 × 70 mm | 3.7 V |
Frequently asked questions
What size is a AAA battery?
10.5 mm across and 44.5 mm long — 0.41 × 1.75 inches.
What voltage is a AAA?
1.5 V (Alkaline).
What is another name for a AAA?
LR03, R03, MN2400, Micro — all the same cell.
Can I use a A23 instead of a AAA?
They are the same diameter, 10.5 mm, and different lengths: 44.5 mm against 28.5. A A23 is thinner, so it may rattle or lose contact, and it holds less. Same voltage, so nothing is damaged by trying.