Biweekly Payments: Thirteen Payments, Not a Lower Rate
The biweekly idea is a calendar fact, not a discount. Half of the monthly payment, paid every two weeks, is 26 half-payments in a 52-week year. Twenty-six halves are 13 full payments. The note was priced for 12. The thirteenth payment is the entire strategy. The interest rate does not change.
This page runs that on the sample the calculator opens with: $300,000 at 6.5% for 30 years, no extra amount typed in. You can set Payment Frequency to Bi-weekly and watch the same inputs.
The monthly year, for scale
Left on Monthly, the payment is $1,896.20. Three hundred sixty payments produce $382,633 of interest. The first payment splits into $1,625.00 of interest and $271.20 of principal. If the first payment is October 2026, the term runs to October 2056. Nothing in the biweekly plan changes those inputs. It only changes how often money arrives.
What the bi-weekly toggle does
The page takes the monthly payment and cuts it in half: $948.10. It then charges interest 26 times a year, using the annual rate divided by 26, and keeps drafting until the balance is under a cent.
On this sample that is 628 half-payments. Divide by 26 and the loan is over in about 24.2 years, not 30. Counted as 14 days per row from October 1, 2026, the last draft falls in October 2050. Interest over those 628 rows is $294,512. Against the monthly schedule, that is about $88,122 less interest and about 70 months off the term.
A row in that table is two weeks. 628 is not 628 months. The first bi-weekly row is $750.00 interest and $198.10 principal, because a two-week slice of 6.5% on $300,000 is $750, and half of $1,896.20 is $948.10.
The same extra payment, sent monthly
One twelfth of $1,896.20 is $158.02. Put that in Extra Monthly Payment, leave the frequency on Monthly, and clear the one-time field. The loan finishes in 290 months — 70 months early — with $295,377 of interest. Interest avoided versus the plain monthly loan is about $87,256.
| Plan | What you send | Interest | When it ends |
|---|---|---|---|
| Monthly, nothing extra | $1,896.20 × 12 | $382,633 | 360 months |
| Bi-weekly toggle | $948.10 × 26 | $294,512 | 628 half-payments (~24.2 years) |
| Monthly plus $158.02 | $2,054.22 × 12 | $295,377 | 290 months |
The two “extra payment a year” plans land within about $865 of each other on this loan. Bi-weekly is slightly ahead here because this calculator accrues interest every two weeks, so a bit of principal drops inside the month instead of at month-end. A servicer that still accrues once a month, and simply posts 26 halves against that monthly interest, will sit nearer the $158 plan. The extra-payments guide runs the one-extra-payment idea on a larger loan and gets the same shape of result.
Fees, and where the extra actually goes
A company that offers to split your payment for you charges a setup fee and a draft fee to move money you can move yourself. The table above has no line for that fee. A standing extra of $158.02, or one full extra payment you send once a year and mark for principal, keeps it.
The failure mode is labeling. Some servicers hold an early draft as next month’s installment, or in a suspense balance, and keep charging interest on the old principal. This page assumes every extra dollar reduces principal immediately. Your note decides whether that is true. If the note has a prepayment penalty, price the penalty before treating $88,122 as money you will keep. The payoff-timeline guide lists what to look for in that clause.
When the calendar is a bad fit
If you are paid once a month, 26 drafts means two months each year with three withdrawals. The budget has to cover those months, not the average month. If the bill includes escrow and the servicer will not split it, the monthly extra is the cleaner version of the same thirteenth payment.
Bi-weekly does not renegotiate 6.5%. You are choosing to pay more dollars per year so that later years never happen. If those dollars are more useful somewhere else — a higher-rate balance, or cash you may need — the extra-payments guide is the comparison, not a second calculator trick.