Battery Size Guide
Find the right battery size for common household devices.
Quick answer: enter your details below and click Show Battery Size — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
B
500 New Tools
Enter your details below.
How to use
- Choose a device.
- Click Show Battery Size.
- Read the typical battery size and the rechargeable tip.
About this tool
Choose a device and the tool tells you the battery size it typically uses, plus a note on rechargeable options. Devices vary by model, so always check the device itself or its manual — this guide covers the common case, not every variant.
Frequently asked questions
Why do smoke alarms use 9V batteries?
Because many older alarms were designed around the 9V block. Newer alarms often use a sealed lithium cell instead.
Should I trust this guide over the device?
No. The device or its manual wins — models vary, and this guide covers the common case.