Yenra original fictional refinance example — September 6, 2026
Not a quote or personalized calculator.
You may reuse this original teaching example for personal or commercial purposes.

All loans start today with $300,000 principal. Keep: 6.75%, 300 months, no new costs. Refinance: 6%, either 300 or 360 months, $4,500 costs paid separately in cash. No financed costs or cash-out.
Monthly rate r = annual nominal rate / 12. Payment = P*r/(1-(1+r)^(-n)). Remaining interest = n*payment-P. Add cash costs separately. Use unrounded payments for totals; display to cents. CSV stores ten decimal places. Actual servicer rounding may differ.
Same-term monthly saving = $139.8303711814. Simple cash-flow break-even = 4500/saving = 32.1818497797 months (during month 33). Longer-term remaining interest plus costs exceed keeping the loan by $30,194.1944735951.
Assume level monthly payments to completion. Exclude taxes, insurance, mortgage insurance, penalties, tax effects, investment returns and discounting. Simple break-even does not compare balances at an early sale.