This live spreadsheet will help you compare side by side either a refinance, or a new purchase. Enter your current information Column C (mortgage amount, interest rate, and length). If you have a second mortgage, you can enter it as well. if you don't, simply zero out those numbers. Then, enter your proposed changes in column D and see how they compare. In the example below, you can see how a $400K mortgage at 7% with a $55K HELOC (or second mortgage) actually costs more per month than a $625K mortgage at 5%. There are more details to consider, but this is a good starting point.
Always check with your accountant to make sure how this is applicable to you!
