every 2 weeks vs 12 payments–one a month, which means you are actually making 1 extra monthly payment per year. this will lower your interest rate.
There are companies that do this for you for a fee, so your savings really don’t materialize. some banks won’t allow you to do it…depends upon your bank.
You could always add more to the principal of the loan every month and it will also shorten the life of the loan.