I’d like to figure out what my monthly payment will be. Is there a formula we can use? I know there are mortgage calculators online- but I’d like to figure out how the change in APR % affects the monthly payment (including taxes and insurance).
Unfortunately, there is no fast-and-simple formula for that. Most loan officers, etc. use special financial calculators or specailly designed computer spreadsheets to do those calculations. I do have such a spreadsheet, so if you want to e-mail me the figures I can come up with some (approximate) numbers for you.