Mortgage Calculator
The payment, what the loan costs in total, when mortgage insurance comes off, and what an extra payment is actually worth.
The loan
Borrowing $382,500 at 90.00% LTV. Above 80%, so mortgage insurance applies.
Taxes, insurance & dues
Assumptions
Total monthly payment
$3,288.07
$2,512.75 principal & interest, plus escrows and PMI
Interest costs more than the house. Over the full term you would pay $522,093 in interest on a $382,500 loan — 136.49% of what you borrowed.
| Principal & interest | $2,512.75 |
|---|---|
| Taxes & insurance | $600.00 |
| HOA | $0.00 |
| Mortgage insurance | $175.31 |
| Total interest over the term | $522,093136.49% of the amount borrowed |
| First payment split | $2,191.41 interest$321.34 principal |
| Balance after five years | $359,568 |
| Payoff with extra payments | 24 yr 1 mo71 payments earlier |
| Interest saved | $121,412 |
| PMI cancellation | Month 68 on requestMonth 78 automatically · $13,674 paid in total |
Estimates only. Your actual payment depends on the rate you are quoted, your credit and reserves, the property's real tax assessment and insurance premium, and your lender's own fees. Not a loan commitment or an offer of credit.
The monthly payment is the least useful number here
Every mortgage calculator returns a payment, and the payment is the one figure you will find out anyway — it is on the Loan Estimate, and your lender will tell you. The numbers worth a calculator are the ones nobody volunteers.
Start with the total. On the default scenario — $382,500 at 6.875% over thirty years — the interest comes to about $522,000. That is roughly 136 percent of what was borrowed: you repay the loan, and then you repay it again with interest on top. It is not a scandal, it is what borrowing money for three decades costs, but it reframes what an eighth of a point is worth. Rate shopping is the highest-leverage thing you can do, and it is worth far more than negotiating any fee at closing.
Then look at the first payment. About $2,191 of interest and $321 of principal. Five years of payments retire under six percent of the balance. This surprises people, but the mechanism is simple: interest accrues on the balance, and early on the balance is nearly the whole loan. It is also why extra payments made early are worth so much more than the same dollars later — they remove principal that would otherwise accrue interest for the next twenty-nine years.
Which is the third number: $200 a month saves about $121,000 and retires the loan 71 payments early. Whether you should is a separate question — an extra payment earns a guaranteed return equal to your rate, which is compelling at 7% and much less so at 3%, and an investor may well do better deploying that money elsewhere. But the magnitude is worth seeing before deciding.
Finally, mortgage insurance — the one that costs people real money through pure inattention. Under the Homeowners Protection Act there are two thresholds, and both are measured against the original property value, not today’s. At 80 percent you can request cancellation in writing. At 78 percent the servicer must remove it automatically, without being asked. On the default scenario those fall at month 68 and month 78 — nearly a year apart, at $175 a month.
Nobody writes to tell you the 80 percent point has arrived. The automatic termination is the servicer’s obligation; the request is yours, and it is worth diarising. Extra payments move both dates earlier, which is a second, quieter return on paying ahead.
Methodology
- Payment:
P = L × i(1+i)ⁿ / ((1+i)ⁿ − 1), computed exactly and then rounded to the cent, which is what a servicer bills. - The schedule is walked month by month in integer cents, rounding interest to the cent each month — again, what a servicer does. The final scheduled payment absorbs the rounding residual, so a thirty-year loan takes 360 payments rather than appearing to need 361.
- PMI is charged on the original loan amount and the payment is fixed until termination, which is the conventional-loan convention. Termination points are found where the balance reaches 80% and 78% of the original property value.
- Extra payments are applied to principal on top of the scheduled payment every month, and the saving is the difference in total interest between the two schedules.
Excluded: rate changes on an adjustable loan, recasting, escrow analysis adjustments, late fees, and any tax treatment of mortgage interest. Property taxes and insurance are held flat, which they will not be — both tend to rise, so a long-run payment estimate is optimistic by construction.
Frequently asked questions
- How much interest will I pay over 30 years?
- Usually more than you borrowed. On $382,500 at 6.875% for thirty years it is about $522,000 — roughly 136% of the loan. That figure moves enormously with the rate: a point lower saves tens of thousands, which is why shopping the rate is worth more than almost anything else you can do at closing.
- Why is my first payment almost all interest?
- Because interest is charged on the balance, and at the start the balance is the whole loan. On the default scenario the first payment puts about $2,191 toward interest and $321 toward principal. Five years in you have retired under 6% of the balance. The schedule is not unfair, but it is front-loaded in a way most people find surprising the first time they see it.
- When does PMI come off?
- Under the Homeowners Protection Act, two points matter and both are measured against the ORIGINAL property value, not today's. At 80% you may request cancellation in writing; at 78% the servicer must remove it automatically. On the default scenario those land at month 68 and month 78. Nobody writes to remind you about the 80% point, which is why borrowers routinely pay for it for months longer than they had to.
- Is it worth paying extra on my mortgage?
- That depends on what else you would do with the money — an extra payment is a guaranteed return equal to your rate, which is a genuinely good return at 7% and a poor one at 3%. What is not in question is the arithmetic: $200 a month on this loan saves about $121,000 in interest and retires it 71 payments early. Early payments do far more than late ones, because they remove interest that would otherwise compound for decades.
- Should I take a 15-year mortgage instead?
- It costs more monthly and dramatically less in total — typically less than half the interest of a thirty-year. The trade is flexibility: a thirty-year with voluntary extra payments gets you most of the same result while letting you stop in a bad month, whereas a fifteen-year payment is an obligation. For an investor the flexibility usually wins; for someone who will not actually make the extra payments, the commitment does.
- Does this include taxes and insurance?
- Yes. The headline figure is the full monthly payment — principal, interest, property taxes, insurance, HOA dues and mortgage insurance where it applies. Principal and interest is shown separately because that is the part the loan terms actually control; everything else varies with the property.
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