lol Stewies Mom its not that complicated to use the chart
http://yorkiepassion.com/growthchart.htm
example if your pup is 3 1/2 lbs @ 5 months each lb equals 16 ounces
you need to convert to ounces
16
16
16
8
-----
56 ounces
now look to the left of the chart for how many weeks your baby is 5 months = 20 weeks follow accross to find 56 oz or close to it
pup should be about 5lbs BUT remember this is just a gage some grow fast others slow.
hope this helps