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Battery sizes chart

Every common consumer battery, by dimensions, voltage and capacity — from AA and AAA to C, D, 9V and the coin cells. Sizes are not interchangeable: a device is built for one form factor. Below is the full reference, plus the cheapest real cost per battery we track for the everyday sizes.

SizeIECVoltageDimensionsCapacity (mAh)Common usesCheapest
AALR61.5V50.5 × 14.5 mm~1,800–2,700Remotes, toys, flashlights, controllers$0.31/ea
AAALR031.5V44.5 × 10.5 mm~850–1,200Remotes, small electronics, mice$0.25/ea
CLR141.5V50 × 26.2 mm~6,000–8,000Larger flashlights, radios, toys—
DLR201.5V61.5 × 34.2 mm~12,000–18,000High-drain flashlights, boomboxes—
9V6LR619V48.5 × 26.5 × 17.5 mm~500–600Smoke detectors, multimeters—
CR2032CR20323V20 × 3.2 mm (coin)~225Key fobs, watches, motherboards—
CR123ACR173453V34.5 × 17 mm~1,500Cameras, tactical flashlights, sensors—
AAAALR611.5V42.5 × 8.3 mm~600Styluses, laser pointers—

Dimensions are the IEC/ANSI standard; capacity is typical alkaline (rechargeable NiMH differs). Prices are the cheapest real cost per cell we track, live from Amazon US, alkaline only — a dash means we don’t track that size.

Cheapest batteries right now

Live from the catalog, ranked by real cost per battery — cheapest first.

Buy by cost per cell, not per pack

The one number that matters when you restock is cost per battery, and the pack size hides it: the same AA can cost 3× more per cell in a 4-pack than a 48-pack. Alkalines keep for a decade in a cool drawer, so the big pack is almost always the right buy — the checkout 4-pack is the most expensive way to own a battery.

See the live rankings

Cheapest AA & AAA batteries per cellEvery pack ranked by real cost per battery.Open Energizer vs DuracellWhich is actually cheaper per battery.Compare

Frequently asked

What is the difference between AA and AAA batteries?▾

Both are 1.5V, but AA is physically larger (50.5 × 14.5 mm) and holds more energy — roughly 1,800–2,700 mAh versus 850–1,200 mAh for AAA (44.5 × 10.5 mm). They are not interchangeable: a device is built for one size. AA lasts longer between changes because it holds more charge.

Are more expensive batteries worth it?▾

For everyday alkaline use — remotes, clocks, toys — store brands run about half the cost per cell of name brands and use the same alkaline chemistry, so the difference is mostly the label. Lithium (e.g. Energizer Ultimate) costs more per cell but lasts far longer in high-drain gear like cameras and cold-weather sensors — that is a cost-per-hour win, not a cost-per-battery one.

What battery does a smoke detector use?▾

Most smoke detectors use a 9V battery (48.5 × 26.5 × 17.5 mm), though many newer models use two or three AAs. Use lithium for smoke detectors if the manufacturer allows it — it holds voltage far longer, so the low-battery chirp comes years later instead of months.