The bi-weekly idea
Instead of 12 monthly payments a year, you pay half a payment every two weeks. Two months a year have three payment periods, so you end up making 26 half-payments — one full extra payment annually. That extra payment is 100% principal, so it compounds into years of saved interest.
The catch
The savings don’t come from the bi-weekly timing — they come from the extra 13th payment. You can get the identical result by adding one-twelfth of your payment to each monthly payment, with none of the friction:
- No enrollment fee (programs often charge $300–$400 plus $2–$4 per payment)
- No risk of the servicer parking your money until a full payment lands
- You can pause or adjust it any month
This calculator shows the payoff time and interest saved from that one extra annual payment, plus what the true bi-weekly half-payment would be.
Who benefits most
Borrowers early in a long loan at a moderate-to-high rate. If you’re 20 years into a 30-year note, the remaining interest is small and so is the benefit. If you just closed on a 30-year loan at 6.5%, the extra payment can remove four to five years.
Better alternatives to compare
- A fixed extra principal amount you choose
- A mortgage recast if you have a lump sum and want a lower required payment
- A shorter refinance term if rates have dropped — check the break-even