You don't need a formal biweekly plan, but you do need to tell the servicer where the extra money goes. A true biweekly plan has you pay half your payment every two weeks. With 52 weeks in a year, that's 26 half-payments, or 13 full payments instead of 12, so you make one extra full payment a year. Most modern servicer portals let you get the same result by adding extra principal to your regular monthly payment, no separate biweekly program required. The critical step, whichever route you take: explicitly instruct the servicer to apply the extra amount to principal on the current statement. Otherwise many servicers park the extra money toward the following month's payment, and you get none of the acceleration benefit. So yes, in practice, confirm that instruction rather than assume it. What one extra payment a year is worth depends heavily on your rate. At a higher illustrative rate, say around 7%, that single extra annual payment can take roughly six years off a 30-year loan. At very low rates the same extra payment does far less, because so little of each payment is interest to begin with. Run it against your own rate and balance to see what it's actually worth for you.