how to age trator

[mig welder]

Hi there just wondering if anyone knows how to age a kubota from the serial no.I've a b4200 and a b5100 and would like to know their age.
Thanks in advance

 

[Tig]

A dealer can look up the serial number and tell you when the tractor was first sold.
There is also a site where people post the serial numbers and year of their tractor. It's not as accurate or complete but may give you an idea. I'll see if I can find it.