I have a mortgage loan $125,000 and I pay $300 off loan every two weeks, the fixed rate is 8.50%. I am locked in at this rate for next 24mths (2yrs).
The current variable rate is 6.25% and to break from the existing fixed rate contract will cost me $3,200.
Is there a formula in Excel that I can use to compare the two rates and loan amounts using the 2yr period?
i.e. $125,000 @ 8.50% for the next 2yrs with repayments of $300 every two weeks compared to
$128,200 @ 6.25% for the next 2 yrs with repayments of $300 every two weeks. Is it worth changing over?

Many thanks

Carl