I have no idea if this is close to the actual. But here is a calculator I found that helped me compare what my debt will look like after 4 years if I don't pay interest on my unsub loans. Hopefully, it will help someone.
<a href="http://www.usagroup.com/borrowing/calculators/interestcap.htm" target="_blank">http://www.usagroup.com/borrowing/calculators/interestcap.htm</a>
<a href="http://www.usagroup.com/borrowing/calculators/interestcap.htm" target="_blank">http://www.usagroup.com/borrowing/calculators/interestcap.htm</a>