$500K House with 20% Down Payment
The classic home-buyer setup: a $500,000 home with a $100,000 (20%) down payment, leaving a $400,000 loan at 7% for 30 years. A pre-filled mortgage calculator scenario.
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Your inputs
Applied 100% to principal
Loan amount: $400,000
Results
Monthly P&I payment
$2,661
Principal & interest, before taxes & insurance
Total interest
$558,036
Total loan cost
$958,036
Payoff time
30.0 years
Scheduled term, no extra payments
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Amortization over time
Year-by-year breakdown
| Year | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | $31,935 | $4,063 | $27,871 | $395,937 |
| 2 | $31,935 | $4,357 | $27,578 | $391,580 |
| 3 | $31,935 | $4,672 | $27,263 | $386,908 |
| 4 | $31,935 | $5,010 | $26,925 | $381,898 |
| 5 | $31,935 | $5,372 | $26,563 | $376,526 |
| 6 | $31,935 | $5,760 | $26,174 | $370,766 |
| 7 | $31,935 | $6,177 | $25,758 | $364,590 |
| 8 | $31,935 | $6,623 | $25,311 | $357,967 |
| 9 | $31,935 | $7,102 | $24,833 | $350,865 |
| 10 | $31,935 | $7,615 | $24,319 | $343,250 |
| 11 | $31,935 | $8,166 | $23,769 | $335,084 |
| 12 | $31,935 | $8,756 | $23,178 | $326,328 |
| 13 | $31,935 | $9,389 | $22,546 | $316,939 |
| 14 | $31,935 | $10,068 | $21,867 | $306,871 |
| 15 | $31,935 | $10,796 | $21,139 | $296,075 |
| 16 | $31,935 | $11,576 | $20,359 | $284,500 |
| 17 | $31,935 | $12,413 | $19,522 | $272,087 |
| 18 | $31,935 | $13,310 | $18,624 | $258,777 |
| 19 | $31,935 | $14,272 | $17,662 | $244,504 |
| 20 | $31,935 | $15,304 | $16,630 | $229,200 |
| 21 | $31,935 | $16,410 | $15,524 | $212,790 |
| 22 | $31,935 | $17,597 | $14,338 | $195,193 |
| 23 | $31,935 | $18,869 | $13,066 | $176,325 |
| 24 | $31,935 | $20,233 | $11,702 | $156,092 |
| 25 | $31,935 | $21,695 | $10,239 | $134,396 |
| 26 | $31,935 | $23,264 | $8,671 | $111,133 |
| 27 | $31,935 | $24,945 | $6,989 | $86,187 |
| 28 | $31,935 | $26,749 | $5,186 | $59,438 |
| 29 | $31,935 | $28,682 | $3,252 | $30,756 |
| 30 | $31,935 | $30,756 | $1,179 | $0 |
Features
- Monthly principal & interest payment
- Total interest and total loan cost
- Year-by-year amortization schedule
- Extra-payment payoff & interest savings
- Shareable result card + CSV export
Scenario Benchmark
Key figures for $500K House with 20% Down Payment.
Monthly P&I payment
$2,661
Total interest
$558,036
Total loan cost
$958,036
Payoff time
30.0 years
Frequently asked questions
How the maths works
A fixed-rate mortgage uses amortization: every payment is split between interest on the remaining balance and principal repayment. Early on, interest dominates; later, principal does — the schedule makes this visible year by year.
- 1Start with the loan amount: home price minus down payment.
- 2Divide the annual rate by 12 for a monthly rate r.
- 3Monthly payment M = L·r / (1 − (1+r)^−n), where L is the loan and n is the number of months.
- 4Each month interest = balance·r and the rest of the payment reduces principal; any extra payment goes 100% to principal.
Figures are principal & interest only. Property taxes, insurance and PMI are not included, and results are illustrative, not a loan offer.
Everything you need to know
What is amortization?
Amortization is the process of paying down a loan with equal monthly payments, where each payment covers the interest accrued on the remaining balance plus a portion of the principal.
Because the balance shrinks, the interest portion falls over time and the principal portion grows — the reason early payments feel like "all interest".
Should I pay off my mortgage early?
Extra monthly payments go straight to principal, which shortens the term and cuts total interest — often by tens of thousands of dollars.
Whether it is the best use of your cash depends on your rate versus the return you could earn elsewhere, but the calculator makes the trade-off concrete.
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