Find the right battery size for any device with our comprehensive battery size chart. From car battery sizes to watch battery sizes, we cover all battery types and applications.
Common battery applications
Understanding battery types and sizes is crucial for finding the right power solution for your device
Car battery sizes and automotive applications
Common sizes for home devices
Small coin cell batteries
Smoke alarms and security systems
Comprehensive reference for all common battery sizes and their specifications
| Group Size | Dimensions (L×W×H) | CCA Range | Common Applications |
|---|---|---|---|
| Group 24 | 10.25" × 6.81" × 8.88" | 550-800 CCA | Mid-size cars, SUVs |
| Group 35 | 9.06" × 6.88" × 8.88" | 600-750 CCA | Honda, Nissan, Toyota |
| Group 65 | 12.06" × 6.81" × 7.88" | 750-850 CCA | Large cars, trucks |
| Group 75 | 9.06" × 7.00" × 8.50" | 650-750 CCA | GM vehicles |
| Group 78 | 10.25" × 7.00" × 7.69" | 700-800 CCA | GM trucks, SUVs |
10.5mm × 44.5mm
14.5mm × 50.5mm
26.2mm × 50mm
34.2mm × 61.5mm
26.5mm × 17.5mm × 48.5mm
68mm × 68mm × 115mm
10.3mm × 28.5mm
| Battery Type | Diameter × Height | Voltage | Common Uses |
|---|---|---|---|
| CR2032 | 20mm × 3.2mm | 3V | Watches, calculators, key fobs |
| CR2025 | 20mm × 2.5mm | 3V | Thin watches, fitness trackers |
| CR2016 | 20mm × 1.6mm | 3V | Ultra-thin devices |
| SR626SW | 6.8mm × 2.6mm | 1.55V | Analog watches |
| SR621SW | 6.8mm × 2.1mm | 1.55V | Small watches |
Step-by-step guide to determine the right battery size for your specific application
Check your device manual, existing battery, or manufacturer specifications for the required battery type and size.
Measure the battery compartment or existing battery to ensure proper fit. Consider length, width, height, and terminal placement.
Match the voltage exactly. Using incorrect voltage can damage your device or cause poor performance.
Higher capacity (mAh or Ah) means longer runtime. Choose based on your usage patterns and replacement frequency preferences.
Choose between alkaline, lithium, NiMH, or other chemistries based on performance requirements and cost considerations.
Critical information about smoke detector battery requirements for home safety
Most common type. Replace annually or when low battery chirp begins.
Newer models often use AA batteries for longer life and better performance.
No battery replacement needed. Replace entire unit after 10 years.
Understanding when batteries can be substituted and compatibility considerations
Same size (AA, AAA, etc.) can usually be substituted. Note: NiMH has slightly lower voltage (1.2V vs 1.5V).
Higher capacity batteries of the same size and voltage can always replace standard ones.
Many watch batteries have equivalent numbers (e.g., SR626SW = 377 = AG4).
Never substitute batteries with different voltages (e.g., 1.5V for 3V) as this can damage devices.
Batteries must fit properly in the compartment. Forcing wrong sizes can damage contacts.
Don't mix alkaline and rechargeable batteries in the same device.
Common questions about battery size charts and compatibility
Check your owner's manual for the recommended battery group size, or look at the label on your current battery. You can also use online battery finder tools by entering your vehicle's year, make, and model. Common automotive battery sizes include Group 24, 35, 65, and 75, each with specific dimensions and terminal configurations.
The numbers in watch battery sizes indicate dimensions: CR2032 is 20mm diameter × 3.2mm thick, while CR2025 is 20mm diameter × 2.5mm thick. Both provide 3V, but CR2032 has higher capacity due to its greater thickness. CR2025 is used in thinner devices where space is limited. Always match the exact size specified by your device manufacturer. See more at 2025 vs 2032
Yes, you can safely use a higher capacity battery of the same size and voltage. Higher capacity (measured in mAh or Ah) simply means longer runtime between replacements or charges. However, ensure the physical dimensions are identical and the voltage matches exactly. Higher capacity batteries may cost more but provide better value through extended operation time.
Use the exact battery size specified by your smoke detector manufacturer - typically 9V or AA batteries. For maximum safety and longevity, choose lithium batteries over alkaline as they last longer and perform better in temperature extremes. Consider upgrading to 10-year sealed smoke detectors with built-in lithium batteries that eliminate the need for battery replacement during the unit's lifespan.
Yes, rechargeable batteries (NiMH) are manufactured in the same standard sizes as alkaline batteries - AA, AAA, C, D, and 9V. They fit in the same devices and battery compartments. However, rechargeable batteries typically provide 1.2V compared to 1.5V for alkaline batteries. Most devices work fine with this slight voltage difference, but some may show reduced performance or shorter runtime.
Battery codes indicate size, chemistry, and sometimes capacity. For coin cells: CR2032 means Lithium (CR), 20mm diameter, 3.2mm thick. For automotive: Group 24 refers to standardized dimensions. Watch batteries may have multiple equivalent numbers (377 = SR626SW = AG4). Always check your device manual or existing battery label for the correct code, and use our battery size chart for cross-reference information.
Our battery experts can help you identify the correct battery size for any application. From automotive battery sizes to specialty watch batteries, we have the expertise to guide your selection.