Battery Sizes
Cell dimensions, voltage, and typical applications for the most common standard battery formats.
Last reviewed on 2026-05-02.
Understanding battery sizes ensures you choose the correct replacement for your devices. This comprehensive guide covers standard battery sizes from AAA to D, button cells, 9V batteries, and rechargeable options.
Standard Cylindrical Battery Sizes
| Size | Diameter | Height | Voltage | Capacity (Alkaline) | Common Uses |
|---|---|---|---|---|---|
| AAA | 10.5mm (0.41") | 44.5mm (1.75") | 1.5V | 1000-1200 mAh | Remotes, small electronics |
| AA | 14.5mm (0.57") | 50.5mm (1.99") | 1.5V | 2400-3000 mAh | Flashlights, toys, controllers |
| C | 26.2mm (1.03") | 50mm (1.97") | 1.5V | 7500-8000 mAh | Flashlights, portable radios |
| D | 34.2mm (1.35") | 61.5mm (2.42") | 1.5V | 15000-20000 mAh | Large flashlights, boomboxes |
| 9V | 26.5mm (1.04") | 48.5mm (1.91") | 9V | 500-600 mAh | Smoke detectors, multimeters |
Button Cell Battery Sizes
| Type | Diameter | Height | Voltage | Common Uses |
|---|---|---|---|---|
| CR2032 | 20mm | 3.2mm | 3V | Key fobs, watches, motherboards |
| CR2025 | 20mm | 2.5mm | 3V | Watches, calculators |
| CR2016 | 20mm | 1.6mm | 3V | Watches, small remotes |
| LR44 (AG13) | 11.6mm | 5.4mm | 1.5V | Laser pointers, toys |
| CR1632 | 16mm | 3.2mm | 3V | Car key fobs |
Rechargeable Battery Sizes (NiMH)
| Size | Voltage | Typical Capacity | Replaces | Recharge Cycles |
|---|---|---|---|---|
| AAA | 1.2V | 800-1000 mAh | 1.5V AAA | 500-1000 |
| AA | 1.2V | 2000-2800 mAh | 1.5V AA | 500-1000 |
| C | 1.2V | 4500-6000 mAh | 1.5V C | 500-1000 |
| D | 1.2V | 9000-12000 mAh | 1.5V D | 500-1000 |
| 9V | 8.4V | 200-300 mAh | 9V alkaline | 500-1000 |
How to choose a battery size
Cubic feet, not just floor area
Standard battery sizes by physical dimension: AAA 10.5×44 mm, AA 14.5×50 mm, C 26×50 mm, D 33×61 mm, 9V 17×26×48 mm. Coin cells use a 4-digit code: CR2032 = 20 mm wide × 3.2 mm thick.
Match the size to the contents
Voltage matters as much as size: alkaline AA = 1.5V, NiMH rechargeable AA = 1.2V; the rechargeable will work in most devices but voltage-sensitive ones (cameras, some medical devices) want alkaline. Lithium primary AAs are 1.5V at lower temperatures and weigh less — useful for cold-weather use.
Access matters
A bigger size is only useful if you can reach what you put in it. Lithium-ion (rechargeable) battery codes (18650, 21700, 26650) describe diameter and length in mm, not capacity. mAh ratings vary by chemistry — a "high-capacity" 18650 can be 2,500–3,500 mAh.
Common mistakes
- Picking by floor area when volume is the real constraint.
- Stacking dense items at the back of a long unit and never being able to reach them again.
- Forgetting overhead clearance — some boxes and bins are taller than they look stacked.
Common Battery Equivalents
- LR44 = AG13 = A76 = 357 (alkaline button cells)
- CR2032 = DL2032 = ECR2032 (lithium coin cells)
- AAA = LR03 (IEC) = 24A (ANSI)
- AA = LR6 (IEC) = 15A (ANSI)
- 9V = 6LR61 (IEC) = 1604A (ANSI)
Battery Safety & Storage
Store batteries in cool, dry place (room temperature). Never mix old and new batteries. Remove batteries from devices not used for months. Dispose properly at recycling centers—never throw in regular trash. Keep button batteries away from children (choking/ingestion hazard).