A23 vs A27
Both are 12 V alkaline stacks of nearly identical length. The A23 is 10.3 mm across against 8 mm and holds roughly double the capacity.
Last reviewed
Both are 12 volt batteries built from a stack of tiny cells inside one shell, and both turn up in garage remotes and car alarm fobs. They are almost exactly the same length, which is what makes them easy to confuse, but the A23 is noticeably fatter — 10.3 mm across against 8 — and holds roughly twice as much. They do not interchange: an A27 rattles loose in an A23 holder and an A23 will not go into an A27 one. Match the code on the cell you removed.
- Verdict:
- Same 12 V and nearly the same length — the A23 is the fatter, longer-lasting one
- Interchangeable:
- no
Side-by-side specifications
| Specification | A23 | A27 |
|---|---|---|
| Chemistry | Alkaline | Alkaline |
| Type | Alkaline Battery | Alkaline Battery |
| Nominal voltage | 12 V | 12 V |
| Diameter | 10.3 mm | 8 mm |
| Height | 28.5 mm | 28.2 mm |
| Typical capacity | 40–55 mAh | 18–22 mAh |
| Rechargeable | No | No |
| Also sold as | 23A, MN21, V23GA, 8LR932 | 27A, MN27, V27A, L828 |
Size comparison
These cells do not share a footprint, so one will not sit correctly in the other's compartment.
Same length, different width
28.5 mm against 28.2 mm — three tenths of a millimetre apart end to end. Diameter is what separates them, at 10.3 mm against 8 mm, and that is more than enough to stop either fitting the other's clip.
Runtime
40–55 mAh against 18–22 mAh. Both figures are tiny because neither cell is built for endurance — they exist to fire a short radio burst when you press a button, a few times a day for a couple of years.
Why 12 V from something this small
Each is a stack of eight miniature alkaline cells in series inside one wrapper. That buys the voltage a radio transmitter wants from a package that fits in a keyfob, at the cost of almost all the capacity.
Inside the wrapper
Neither is a single cell. Both are a stack of eight miniature alkaline cells in series inside one shrink-wrapped tube, which is how a battery the size of a pencil stub produces 12 V. It also explains the tiny capacity: the cells are stacked for voltage, and there is very little of each.
Why remotes use 12 V at all
A short-range radio transmitter is easier to design around a higher voltage than around 1.5 V, and the duty cycle is measured in milliseconds per press. Capacity barely matters when the device is asleep almost all the time.
Symptoms of a flat one
Range shortens before the fob stops working. A garage remote that only operates from the driveway rather than the road usually has a tired cell rather than a fault, and these stacks fade rather than dying outright.
Can I use an A27 instead of an A23?
Not directly. The A27 measures 8 × 28.2 mm against 10.3 × 28.5 mm for the A23, 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.
A23 vs A27: common questions
Is the A27 a direct replacement for the A23?
Both are 12 volt batteries built from a stack of tiny cells inside one shell, and both turn up in garage remotes and car alarm fobs. They are almost exactly the same length, which is what makes them easy to confuse, but the A23 is noticeably fatter — 10.3 mm across against 8 — and holds roughly twice as much. They do not interchange: an A27 rattles loose in an A23 holder and an A23 will not go into an A27 one. Match the code on the cell you removed.
What is the difference between the A23 and the A27?
Both are 12 V alkaline stacks of nearly identical length. The A23 is 10.3 mm across against 8 mm and holds roughly double the capacity. In short: same 12 V and nearly the same length — the A23 is the fatter, longer-lasting one.
Are the A23 and the A27 the same size?
No. The A23 is 10.3 × 28.5 mm and the A27 is 8 × 28.2 mm.
Which lasts longer, the A23 or the A27?
The A23. It is rated at 40–55 mAh against 18–22 mAh for the A27 — roughly 2.4× the capacity, though real runtime depends on how much current your device draws.