The CR2032 battery is a lithium button cell battery that produces 3 volts when new. Button cell batteries are used to power devices that use very little energy such as watches or light emitting diodes (LEDs). A CR2032 battery generally lasts a long time, due to the low energy requirement of the device it powers, but if your watch is running slow, or your LED isn't bright, then use a multimeter to do a DIY test on your CR2032.
Set your multimeter to measure direct current (DC) voltage as your CR2032 battery produces DC. Turn the dial or press the appropriate buttons on the front of the meter to get the setting.
Look at your CR2032 battery to ascertain the two polarities. The flat top plate has a "+" symbol embossed on it, meaning positive. The other side is slightly raised, but doesn't have a mark and is the negative terminal.
Put the probe on the end of the red wire from the meter onto the CR2032 battery terminal labelled "+" and put the probe on the end of the black wire onto the other battery terminal.
Look at the multimeter display to read the voltage. It reads 3 volts, if your battery is charged. A reading below 2.5 volts means you need to replace the CR2032 battery.