here is the one i use.....
Basically add one foot to your putting distance for every inch of up elevation, subtract one foot for every inch of down elevation. (Tournament and Championship Greens excepted), then apply the following conversion.
slow greens.................divide by 0.9
standard.......................none needed
fast................................divide by 1.1
very fast.........................divide by 1.2
tournament...................divide by 1.3
championship..............divide by 1.4
Exception for tournament and championship greens: Up elevation as noted above, but for down elevation. subtract the drop AFTER you divide. this has always worked well for me. a little practice and it should for you as well. hopefully :-)