What Are C Batteries? | Size, Voltage & Uses Explained

If you’ve ever stood in the battery aisle wondering what a C battery is and where it fits among all the other sizes, here’s the short answer: a C battery is the medium-sized option that sits between AA and D, built for devices that need more runtime than a AA can deliver but don’t require the bulk of a D. They show up in flashlights, portable radios, toys, and instruments — the gear that drains smaller cells too quickly.

Before you buy, it helps to know what you’re actually looking at. C batteries are standardized, but not all C cells are created equal.

How Big Is a C Battery?

That puts it right between a AA and a D in physical size, and it’s the form factor that matters most when you’re matching a cell to a device.

The positive terminal is a raised button on top, and the negative terminal is the flat base. In the U.S., you’ll see them labeled simply as “C” or “size C,” with the IEC designation LR14 for alkaline and the ANSI code 14A. Other regional names for the same size include U11, HP11, MN1400, and the older “Baby” designation.

This size standardization means any C cell from any brand will physically fit a device built for C batteries — but the chemistry inside matters just as much.

Voltage and Common Types

Most primary C batteries deliver 1.5 volts, but that’s not the whole story. Rechargeable nickel-metal hydride (NiMH) and nickel-cadmium (NiCd) versions typically run at 1.2 volts, which is a real difference when your device expects 1.5V.

The common chemistries break down like this:

• LR14 (alkaline): The everyday disposable option; typically 1.5V with capacities around 6,000–8,000 mAh, though some brands list up to 9,000 mAh.
• R14 (carbon-zinc): The older, cheaper chemistry; roughly 3,800 mAh and best for low-drain devices.
• HR14 (NiMH): Rechargeable and reusable; usually 4,500–6,000 mAh at 1.2V.
• KR14 (NiCd): An older rechargeable chemistry, less common today.

Some specialty C cells come in other voltages like 3V or 3.6V for specific industrial uses, which is why “C” is a size, not a chemistry. Always check your device’s manual for the chemistry and voltage it expects.

Where C Batteries Are Used

C batteries power devices with medium energy demands. Flashlights, boomboxes, radios, toys, and musical instruments are the classic examples — equipment that runs for hours at a stretch and needs more capacity than a AA can offer without the weight of a D cell.

One important note: a C cell is not directly interchangeable with AA or D batteries. Adapters exist that let you drop smaller batteries into a C-sized slot, but you lose capacity when you do. For a device that needs real runtime, the proper C cell is the honest choice. If you’re deciding which brand and type suits your gear, our tested roundup of the best C batteries breaks down the top options side by side.

The Bottom Line

The two things people get wrong are assuming every C cell is the same voltage and assuming all C cells hold the same charge — neither is true.

Check your device’s manual for the right chemistry, avoid mixing old and new batteries, and don’t use rechargeable 1.2V cells in gear that specifically requires 1.5V. Get those basics right and any C battery you pick will work exactly as intended.