How do I calculate california portion of student loan interest-I lived in NY 11 mos in 2016

[rdkcastro5]

I moved to NY feb. 2016. I pay student loan interest and TurboTax asks how much is the CA portion of my student loan interest?  How do I calculate that? The box is blank

[AnthonyC]

The easiest method is to just use a proportional calculation since you likely made equal payments every month.

For example, for NY take (11 / 12) x Amount of Interest and for CA take ( 1 / 12 ) x Amount of interest.  So, using simple numbers if you paid $1,200 in total interest over the year, then, using the formula above, $1,100 would be attributable to NY and $100 to CA. 

If you didn't make equal or somewhat equal payments - i.e you made one big payment for the one month in CA - then you may want to tally up the interest attributable to each monthly payment (you can find the information on your statements).