Battery Sizes: Dimensions of AA, AAA, C, D, 9V, Coin and Lithium Cells
Exact dimensions, voltages and typical capacities of household batteries, from AAA to D, 9V, coin and button cells and rechargeable lithium cells, plus how to read the codes printed on them.
An AA battery is 14.5 mm (0.57 in) wide and 50.5 mm (1.99 in) long; an AAA is 10.5 × 44.5 mm (0.41 × 1.75 in). A C cell is 26.2 × 50 mm, a D cell 34.2 × 61.5 mm, and a 9V is a 48.5 × 26.5 × 17.5 mm block. These are the maximum sizes set by IEC 60086; real cells are within a few tenths of a millimeter.
- AA
- 14.5 × 50.5 mm
- AAA
- 10.5 × 44.5 mm
- D
- 34.2 × 61.5 mm
- CR2032 coin
- 20 × 3.2 mm
On this page
Battery size chart: cylindrical and 9V
Dimensions are the maximum diameter and overall length (including the positive button) allowed by IEC 60086-2. Capacities are typical for alkaline cells at low drain; they fall sharply in high-drain devices such as cameras.
| Size | IEC code | Diameter × length (mm) | Inches | Voltage | Typical capacity |
|---|---|---|---|---|---|
| AAAA | LR61 | 8.3 × 42.5 | 0.33 × 1.67 | 1.5 V | about 550-650 mAh |
| AAA | LR03 | 10.5 × 44.5 | 0.41 × 1.75 | 1.5 V | 1,000-1,200 mAh |
| AA | LR6 | 14.5 × 50.5 | 0.57 × 1.99 | 1.5 V | 2,500-3,000 mAh |
| C | LR14 | 26.2 × 50.0 | 1.03 × 1.97 | 1.5 V | 6,000-8,000 mAh |
| D | LR20 | 34.2 × 61.5 | 1.35 × 2.42 | 1.5 V | 12,000-18,000 mAh |
| N | LR1 | 12.0 × 30.2 | 0.47 × 1.19 | 1.5 V | about 800-1,000 mAh |
| 9V (PP3) | 6LR61 | 48.5 × 26.5 × 17.5 | 1.91 × 1.04 × 0.69 | 9 V | 500-600 mAh |
| A23 | 8LR932 | 10.3 × 28.5 | 0.41 × 1.12 | 12 V | about 50 mAh |
Typical weights for alkaline cells: AAA about 11.5 g (0.4 oz), AA about 23 g (0.8 oz), C about 66 g (2.3 oz), D about 135-145 g (4.8-5.1 oz) and 9V about 45 g (1.6 oz).
Same battery, different names
The letter names (AA, C, D) come from the American National Standards Institute; the rest of the world prints IEC codes, and brands add their own numbers. They are interchangeable when the size and chemistry match.
| Common name | IEC alkaline | IEC zinc-carbon | Japan / China | Other names |
|---|---|---|---|---|
| AAA | LR03 | R03 | UM-4, No. 7 | MN2400, Micro |
| AA | LR6 | R6 | UM-3, No. 5 | MN1500, Mignon |
| C | LR14 | R14 | UM-2, No. 2 | MN1400, Baby |
| D | LR20 | R20 | UM-1, No. 1 | MN1300, Mono |
| 9V | 6LR61 | 6F22 | 006P | PP3, MN1604, E-block |
In IEC codes the letters give chemistry and shape: L alkaline, C lithium manganese dioxide, S silver oxide, P zinc-air, F lithium iron disulfide, and R round. A code with no chemistry letter (R6) is zinc-carbon, the cheapest and lowest-capacity type.
Coin and button battery sizes
Lithium coin cells (CR) run at 3 V. Their number gives the size: first two digits are the diameter in mm, the last two the thickness in tenths of a mm.
| Cell | Diameter × thickness | Typical capacity | Common uses |
|---|---|---|---|
| CR2032 | 20 × 3.2 mm | about 220-240 mAh | Key fobs, motherboards, scales, AirTag-type trackers |
| CR2025 | 20 × 2.5 mm | about 150-170 mAh | Remotes, key fobs, watches |
| CR2016 | 20 × 1.6 mm | about 80-90 mAh | Thin remotes, watches, calculators |
| CR2450 | 24.5 × 5.0 mm | about 600-620 mAh | Smart home sensors, bike computers |
| CR2430 | 24.5 × 3.0 mm | about 280-300 mAh | Car keys, sensors |
| CR1632 | 16 × 3.2 mm | about 130-140 mAh | Car key fobs, tire pressure tools |
| CR1620 | 16 × 2.0 mm | about 75-80 mAh | Car keys, small electronics |
| CR1220 | 12.5 × 2.0 mm | about 35-40 mAh | Laser pointers, small LED lights |
Button cells (1.5 V)
Alkaline (LR) and silver-oxide (SR) button cells share sizes; silver oxide holds its voltage better and lasts longer in watches.
| IEC | Size (mm) | Also sold as | Uses |
|---|---|---|---|
| LR44 / SR44 | 11.6 × 5.4 | AG13, 357, 303, A76 | Calipers, toys, laser pointers |
| LR1130 / SR1130 | 11.6 × 3.05 | AG10, 389, 390 | Calculators, toys |
| LR41 / SR41 | 7.9 × 3.6 | AG3, 392, 384 | Thermometers, small lights |
| SR626SW | 6.8 × 2.6 | 377, AG4 | Wristwatches |
| SR621SW | 6.8 × 2.1 | 364, AG1 | Wristwatches |
Hearing aid batteries
Zinc-air hearing aid cells (1.45 V) are color-coded by size on the pull tab: 10 yellow (5.8 × 3.6 mm), 312 brown (7.9 × 3.6 mm), 13 orange (7.9 × 5.4 mm) and 675 blue (11.6 × 5.4 mm). They start working only once the tab is removed and air reaches the cell.
A swallowed coin cell lodged in a child's esophagus can cause severe burns in as little as two hours. In the US, Reese's Law requires child-resistant packaging for these cells and, since March 2024 (16 CFR Part 1263), battery compartments that children cannot open. Store spares out of reach, tape the terminals of used cells before disposal, and seek emergency care immediately if one may have been swallowed.
Rechargeable and lithium-ion battery sizes
Rechargeable NiMH cells use the same sizes as alkaline cells but run at a lower nominal voltage. Lithium-ion cells use a different naming system: diameter in mm, then length in mm with a trailing zero for "cylindrical".
| Cell | Size (mm) | Inches | Voltage | Typical capacity |
|---|---|---|---|---|
| NiMH AAA | 10.5 × 44.5 | 0.41 × 1.75 | 1.2 V | 800-1,100 mAh |
| NiMH AA | 14.5 × 50.5 | 0.57 × 1.99 | 1.2 V | 1,900-2,800 mAh |
| 14500 Li-ion | 14 × 50 | 0.55 × 1.97 | 3.6-3.7 V | 600-1,000 mAh |
| 16340 / RCR123A | 16 × 34 | 0.63 × 1.34 | 3.6-3.7 V | 550-750 mAh |
| 18650 Li-ion | 18 × 65 | 0.71 × 2.56 | 3.6-3.7 V | 2,500-3,500 mAh |
| 21700 Li-ion | 21 × 70 | 0.83 × 2.76 | 3.6-3.7 V | 4,000-5,000 mAh |
| CR123A (not rechargeable) | 17 × 34.5 | 0.67 × 1.36 | 3 V | about 1,500 mAh |
| CR2 (not rechargeable) | 15.6 × 27 | 0.61 × 1.06 | 3 V | about 800 mAh |
A 14500 lithium-ion cell is the size of an AA but delivers 3.7 V, about 2.5 times an alkaline AA. In a device built for AA batteries it can burn out the electronics. Use 14500 cells only in devices that list them, and look for "1.5 V" on any lithium AA you buy (lithium iron disulfide AAs and regulated 1.5 V USB-rechargeable AAs are safe substitutes).
A NiMH cell's 1.2 V works in nearly all AA devices because alkaline cells spend most of their life between 1.2 and 1.4 V anyway. The exceptions are devices that read the voltage to show a battery gauge, which may report rechargeables as half empty.
Choosing the right size and type
- Read the marking inside the compartment or on the old cell. Match the size code (AA, LR6, CR2032) exactly; similar-looking coin cells differ by fractions of a millimeter.
- For coin cells, measure thickness with a ruler or caliper if the marking is worn: 1.6, 2.0, 2.5 and 3.2 mm are the common thicknesses.
- Pick the chemistry for the load. Lithium AA cells (1.5 V lithium iron disulfide) last longest in cameras and outdoor cold; alkaline suits clocks and remotes; NiMH pays off in game controllers and toys used daily.
- Do not mix old and new cells or different chemistries in one device. The weakest cell can be driven into reverse charge and leak.
- Remove batteries from devices stored for months; alkaline leakage is the most common cause of corroded contacts.
Car and truck starting batteries are sized by group number rather than cell size; those dimensions are in the car battery group size chart. Built-in batteries in phones, watches and laptops are covered with each device: see smartwatch sizes and laptop sizes. To convert between millimeters and inches, use the unit converter.
Frequently asked questions
What are the most common battery sizes?
AA and AAA cover most remotes, toys and wireless devices. C and D cells power larger flashlights and radios, 9V batteries run smoke alarms and test meters, and CR2032 coin cells go in key fobs, scales and computer motherboards.
Are C and D batteries the same length?
No. A C cell is 50 mm long, almost the same as an AA (50.5 mm), but much wider at 26.2 mm. A D cell is both wider (34.2 mm) and longer (61.5 mm). Plastic spacer sleeves let an AA fit a C or D slot, but with a fraction of the capacity.
Can I use a CR2025 instead of a CR2032?
Often yes in an emergency. Both are 20 mm, 3 V lithium coins, but the CR2025 is 2.5 mm thick vs 3.2 mm, so it may not press firmly on the contacts and it holds roughly a third less energy. A CR2016 (1.6 mm) is thinner still.
Is an 18650 the same as an AA?
No. An 18650 lithium-ion cell is 18 × 65 mm, wider and 15 mm longer than an AA, and it runs at 3.6-3.7 V rather than 1.5 V. It will not fit or work in AA devices.
What does the number on a coin battery mean?
The first two digits are the diameter in millimeters and the last two are the thickness in tenths of a millimeter. A CR2032 is 20 mm across and 3.2 mm thick; a CR1632 is 16 mm across and 3.2 mm thick. The letters CR mean lithium manganese dioxide chemistry, round shape.