Where Can I Find A Measurement Chart That Break Down One Inch To Decimal Unit For A Page Border?

You can easily create such a table.
An inch is divided into 4 quarters which are further divided into 4 parts so
each smallest unit of inch is a quarter of a quarter that is 0.25 times 0.25 = 0.0625.
 
More common usage is diving an inch into 8 parts so least count is  0.125