1. Same voltage, different thickness
The CR2450 is 3 volts, like the CR2032, but it’s 24.5 mm wide and 5 mm thick. The CR2032 is 20 mm wide and 3.2 mm thick.
2. More energy
Being thicker, it holds much more energy. A CR2450 can power some devices for far longer than a CR2032 of the same voltage.
3. Where you’ll find it
Bike lights, some medical devices and some larger gadgets. The code is usually printed on the battery compartment or in the manual.
4. Don’t swap them by size
A CR2032 won’t make proper contact in a CR2450 holder, because it’s too thin. Check the code, and never add a thin coin to a thick slot to make it fit.