Help - am I using the wrong calulator??

[Amy Blunck]

Hello,

We are looking into buying a new primary residence and keeping our existing home as a rental (est. $2200/mo) because we have a significant amount of equity in it ($133k), and a low interest rate on that mortgage (3.5%, $1291/mo, including taxes/insurance). We're considering getting a 30 year fixed (4.625%) for our new primary home (est. $2050/mo, including taxes/insurance). I can't figure out the best calculator to use for this. I've tried the Rental Property calculator but I think I'm messing it up when it asks me for purchase price and ARV, and whether it's a cash purchase or loan info. What numbers do I need to be inputting here or am I just using the wrong calculator altogether? Please guide me towards the correct resource if I need a different calculator or tool.

Thanks,

Amy