C vs D
Both 1.5 V alkaline. The D is 34.2 × 61.5 mm against the C's 26.2 × 50 mm, and holds roughly double the energy.
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Both are 1.5 volts. The D is bigger and holds about twice as much, so it runs roughly twice as long. Neither fits the other's compartment — the D is 8 mm wider and over a centimetre longer. There is no performance decision to make here beyond size: fit whichever your device was built for.
- Verdict:
- D for double the runtime, C where a D will not fit
- Interchangeable:
- no
Side-by-side specifications
| Specification | C | D |
|---|---|---|
| Chemistry | Alkaline | Alkaline |
| Type | Cylindrical | Cylindrical |
| Nominal voltage | 1.5 V | 1.5 V |
| Diameter | 26.2 mm | 34.2 mm |
| Height | 50 mm | 61.5 mm |
| Typical capacity | 6000–8000 mAh | 12000–18000 mAh |
| Rechargeable | No | No |
| Also sold as | LR14, MN1400, AM2, R14 | LR20, MN1300, AM1, R20 |
Size comparison
These cells do not share a footprint, so one will not sit correctly in the other's compartment.
Size
34.2 × 61.5 mm against 26.2 × 50 mm. Eight millimetres of diameter and over ten of length — no adapter bridges this pair in the useful direction.
Runtime
12000–18000 mAh against 6000–8000 mAh. Roughly double, for a cell that takes up roughly double the space.
Where each turns up
D cells go into lanterns, large torches and anything left running for hours. C cells appear where a designer wanted more than an AA but did not have room for a D.
Both are getting rarer
Efficient LEDs and lithium packs have taken most of the products that used to need either size. Both are still stocked everywhere, but the range of brands is narrower than for AA, and rechargeable versions in these sizes are a specialist purchase rather than a supermarket one.
Sub-C and other relatives
The C family includes a shorter sub-C cell used inside power tool packs rather than sold loose. If you have opened a cordless tool and found cells that look like short C cells, that is what they are, and they are not a swap for a household C.
Adapters exist here too
C-to-D sleeves are sold and work in the same low-drain cases as AA-to-C, giving D-compartment runtime of roughly half. Better than an AA in the same sleeve, still short of the cell the device was designed around.
Can I use a D instead of a C?
Not directly. The D measures 34.2 × 61.5 mm against 26.2 × 50 mm for the C, 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.
C vs D: common questions
Is the D a direct replacement for the C?
Both are 1.5 volts. The D is bigger and holds about twice as much, so it runs roughly twice as long. Neither fits the other's compartment — the D is 8 mm wider and over a centimetre longer. There is no performance decision to make here beyond size: fit whichever your device was built for.
What is the difference between the C and the D?
Both 1.5 V alkaline. The D is 34.2 × 61.5 mm against the C's 26.2 × 50 mm, and holds roughly double the energy. In short: d for double the runtime, C where a D will not fit.
Are the C and the D the same size?
No. The C is 26.2 × 50 mm and the D is 34.2 × 61.5 mm.
Which lasts longer, the C or the D?
The D. It is rated at 12000–18000 mAh against 6000–8000 mAh for the C — roughly 2.1× the capacity, though real runtime depends on how much current your device draws.
Background reading
The wider questions behind these two codes.