Boss serial numbers are either 4 numbers, 6 numbers, or 6/7 characters with 2 letters and the rest numbers. If you have a Boss serial number with just one letter please double check in case another character is actually a letter. It isn't always next to the other letter. The letter Z may look like a 2 and a zero may actually be a letter O. This tool works by first decoding the Boss date code part of the serial number, then because the date code on Boss devices was repeated it is compared to my database of Boss product dates to narrow it down.
This tool will find the manufacture date of any Boss product including guitar effects pedals, multi-effects processors, drum machines, tuners and metronomes.
For details of my Boss pedal database click here. For Roland products please use the Roland decoder as that has the Roland production dates.
You can find the serial in the battery compartment or on a sticker on the base.