AAA vs AAAA
Both 1.5 V alkaline. The AAAA is 8.3 × 42.5 mm against the AAA's 10.5 × 44.5 mm, with roughly half the capacity.
Last reviewed
Easy to confuse on paper, impossible to confuse in the hand. Both give 1.5 volts, but the AAAA is thinner and a little shorter than an AAA and holds around half the energy. They do not interchange. Count the A's in what your device asks for before you order — that really is the whole difference.
- Verdict:
- One letter apart in the name, about half the cell
- Interchangeable:
- no
Side-by-side specifications
| Specification | AAA | AAAA |
|---|---|---|
| Chemistry | Alkaline | Alkaline |
| Type | Cylindrical | Cylindrical |
| Nominal voltage | 1.5 V | 1.5 V |
| Diameter | 10.5 mm | 8.3 mm |
| Height | 44.5 mm | 42.5 mm |
| Typical capacity | 850–1200 mAh | 500–650 mAh |
| Rechargeable | No | No |
| Also sold as | LR03, MN2400, AM4, R03 | LR61, MN2500, MX2500, E96 |
Size comparison
These cells do not share a footprint, so one will not sit correctly in the other's compartment.
Size
10.5 × 44.5 mm against 8.3 × 42.5 mm. Only 2 mm separates them in length, but the AAAA is a fifth narrower — enough that it rattles loose in an AAA holder.
Runtime
850–1200 mAh against 500–650 mAh. The AAA runs roughly 80% longer in the same device.
Where you meet an AAAA
Active styluses, laser pointers, glucose meters and slim LED lights. It is a niche size, so it is usually dearer per cell and harder to find on a shelf than an AAA.
Reading the name aloud helps
Triple-A and quadruple-A differ by one letter in print and by a syllable in speech, which is exactly why orders go wrong. When ordering, count the letters deliberately, and when searching, the digit forms 3A and 4A are less easily misread.
Very different availability
AAA is among the best-stocked cells in the world; AAAA is a specialist item at several times the price. If a device can take either, the AAA version is the cheaper one to live with by a wide margin.
Neither is a Li-ion look-alike
There is a 3.6 V lithium-ion cell in the AAA form factor — the 10440 — and it must not go into an AAA device. There is no equivalent trap in the AAAA size, which is one fewer thing to get wrong.
Can I use an AAAA instead of an AAA?
Not directly. The AAAA measures 8.3 × 42.5 mm against 10.5 × 44.5 mm for the AAA, so it will not seat properly in the same compartment.
Check before you swap. Batteries with similar dimensions are not always interchangeable. Always verify voltage, chemistry and the requirements printed in your device manual before fitting a replacement.
AAA vs AAAA: common questions
Is the AAAA a direct replacement for the AAA?
Easy to confuse on paper, impossible to confuse in the hand. Both give 1.5 volts, but the AAAA is thinner and a little shorter than an AAA and holds around half the energy. They do not interchange. Count the A's in what your device asks for before you order — that really is the whole difference.
What is the difference between the AAA and the AAAA?
Both 1.5 V alkaline. The AAAA is 8.3 × 42.5 mm against the AAA's 10.5 × 44.5 mm, with roughly half the capacity. In short: one letter apart in the name, about half the cell.
Are the AAA and the AAAA the same size?
No. The AAA is 10.5 × 44.5 mm and the AAAA is 8.3 × 42.5 mm.
Which lasts longer, the AAA or the AAAA?
The AAA. It is rated at 850–1200 mAh against 500–650 mAh for the AAAA — roughly 1.8× the capacity, though real runtime depends on how much current your device draws.
Background reading
The wider questions behind these two codes.
Lithium for cold, weight and high drain; alkaline for everything else
NiMH for anything you replace often, alkaline for anything you forget about
Switch anything you replace more than twice a year
Lithium for standby and extremes, NiMH for anything used often