额外还款计算器
计算额外还款对贷款总利息和还款期限的影响。
Months Saved
113
Months Saved vs Loan Term
公式
Impact of Extra Mortgage Payments
Extra payments applied to principal reduce the balance faster, saving interest and shortening the loan term.
New Payoff Formula
New Months = log(PMT / (PMT - P x r)) / log(1 + r)
Where PMT is the total monthly payment (base + extra), P is the loan balance, and r is the monthly rate.
Why Extra Payments Are So Effective
Strategies
计算示例
A $300,000 loan at 7% for 30 years with an extra $300/month.
- 01Base payment: $1,995.91
- 02Total payment with extra: $1,995.91 + $300 = $2,295.91
- 03Original payoff: 360 months (30 years)
- 04New payoff: approximately 263 months (about 22 years)
- 05Months saved: 360 - 263 = 97 months (about 8 years)
- 06Original total interest: $418,528
- 07New total interest: approximately $303,726
- 08Interest saved: approximately $114,802
常见问题
Should I make extra payments or invest the money?
Compare your after-tax mortgage rate to expected investment returns. If your mortgage is 7% and investments earn 10%, investing wins mathematically. However, the guaranteed return of paying down debt has value. Many people do a mix of both for diversification.
Do I need to tell my lender about extra payments?
Specify that extra payments should be applied to principal, not held for future payments. Most lenders have a line on the payment stub for additional principal. With autopay, you may need to call or log in to set this up correctly.
Is there a penalty for making extra mortgage payments?
Most conventional, FHA, and VA mortgages have no prepayment penalty. Some older loans or commercial mortgages may have penalties for the first 3-5 years. Check your loan documents or ask your servicer before making large extra payments.