Mortgage Calculator
Estimate the full monthly cost of a home — principal, interest, property tax, insurance, HOA dues and mortgage insurance — and see what changing the rate, the term or the down payment is worth.
The address carries whatever you changed, so anyone opening it sees these numbers. Nothing is saved on our side.
Estimated monthly payment
$4,119/mo
Principal, interest, taxes and insurance on a 30-year fixed loan of $520,000.
- Principal & interest82%$3,373
- Property tax14%$596
- Homeowners insurance4%$150
- Total monthly payment$4,119
- $520,000
- $130,000
- 20% of price
- $694,176
- over the life of the loan
- $1,482,675
- excludes the down payment
- —
- 80%
- no PMI
What changes the answer
The two inputs with the most leverage over a mortgage are the rate you are offered and how much you put down. Here is what each is worth on your numbers.
Compare by
| Rate | Monthly | Total interest | vs yours |
|---|---|---|---|
| 5.75% | $3,035 | −$121,728 less in total | |
| 6.25% | $3,202 | −$61,554 less in total | |
| 6.75%yours | $3,373 | — | |
| 7.25% | $3,547 | +$62,855 more in total | |
| 7.75% | $3,725 | +$126,952 more in total |
Every other input is held at what you entered. Rates shown are examples, not quotes — 0.5% either side of your rate is a realistic spread between lenders on the same day.
What one extra payment a month does
Every extra dollar goes straight against the principal, so it cancels all the future interest that dollar would have accrued. On a thirty-year loan the effect is far larger than the money put in.
On top of principal and interest
- Interest saved
- $126,523
- Paid off sooner by
- 4 years 7 months
- Extra paid in
- $61,000
- Total interest instead of $694,176
- $567,653
Where the money goes
Early payments are almost all interest. The balance shifts slowly, and the schedule below shows exactly when.
Loan year
More of your payment goes to principal than to interest from year 21 onward.
| Year | Principal | Interest | Balance |
|---|---|---|---|
| $5,542 | $34,931 | $514,458 | |
| $5,928 | $34,545 | $508,530 | |
| $6,341 | $34,132 | $502,190 | |
| $6,782 | $33,691 | $495,408 | |
| $7,254 | $33,218 | $488,154 | |
| $7,759 | $32,713 | $480,394 | |
| $8,300 | $32,173 | $472,095 | |
| $8,877 | $31,595 | $463,217 | |
| $9,496 | $30,977 | $453,722 | |
| $10,157 | $30,316 | $443,565 | |
| $10,864 | $29,609 | $432,701 | |
| $11,620 | $28,852 | $421,081 | |
| $12,429 | $28,043 | $408,652 | |
| $13,295 | $27,178 | $395,357 | |
| $14,221 | $26,252 | $381,136 | |
| $15,211 | $25,262 | $365,926 | |
| $16,270 | $24,203 | $349,656 | |
| $17,403 | $23,070 | $332,253 | |
| $18,614 | $21,858 | $313,639 | |
| $19,910 | $20,562 | $293,728 | |
| $21,297 | $19,176 | $272,432 | |
| $22,780 | $17,693 | $249,652 | |
| $24,366 | $16,107 | $225,287 | |
| $26,062 | $14,410 | $199,224 | |
| $27,877 | $12,596 | $171,347 | |
| $29,818 | $10,655 | $141,530 | |
| $31,894 | $8,579 | $109,636 | |
| $34,115 | $6,358 | $75,521 | |
| $36,490 | $3,982 | $39,031 | |
| $39,031 | $1,442 | $0 |
How this calculator works
Principal and interest come from the standard amortizing-loan formula. Everything else is a monthly share of an annual cost.
M = L · r ÷ (1 − (1 + r)−n)
- L
- the amount borrowed — purchase price minus down payment
- r
- the monthly rate — the annual rate divided by twelve
- n
- the number of monthly payments — the term in years times twelve
At a rate of zero the formula is undefined and the loan is simply repaid in equal instalments, so M = L ÷ n. Interest is rounded to the cent each month, the way a servicer does it, and the final payment absorbs the rounding difference — which is why the last row of the schedule settles the balance to exactly zero.
The other lines
- Property tax and insurance are annual figures divided by twelve, held flat for the life of the loan.
- HOA dues are entered monthly and added as they are.
- Mortgage insurance is the annual PMI rate applied to the original loan amount, divided by twelve, charged until the balance reaches 78% of the purchase price.
- Total interest is the sum of every interest payment in the schedule, not an approximation.
A worked example
The default figures, calculated step by step, so you can check the arithmetic yourself.
| Purchase price | $650,000 |
|---|---|
| Down payment at 20% | $130,000 |
| Amount borrowed (L) | $520,000 |
| Monthly rate (r) | 0.005625 |
| Number of payments (n) | 360 |
| (1 + r)⁻ⁿ | 0.132725 |
| Principal & interest | $3,372.71 |
| Property tax | $595.83 |
| Homeowners insurance | $150.00 |
| Mortgage insurance | $0.00 |
| Estimated monthly payment | $4,118.54 |
Over the full term that loan costs $694,175.73 in interest — more than the amount borrowed. That is the number most worth understanding before signing.
What actually moves your payment
The interest rate
Half a point either way changes a $520,000 loan by roughly $175 a month and tens of thousands over thirty years. It is worth more than almost anything else you can negotiate.
The term
A shorter loan has a higher payment and far less total interest. This is a trade between monthly comfort and lifetime cost, not a question with one right answer.
The down payment
It lowers the amount borrowed, and crossing 20% removes mortgage insurance entirely — often a bigger jump than the smaller balance alone.
Property tax
Set by your county, not your lender, and it varies enormously between states and even between neighbouring towns. On many homes it is the second largest line after interest.
Insurance
Priced on the property, its age and its risk exposure. Coastal and wildfire regions have seen the sharpest increases, and flood cover is usually separate.
HOA dues
Not part of the mortgage at all, but it comes out of the same budget every month, and it can rise without your loan changing.
Questions people ask
Principal and interest on a fixed-rate loan, plus one twelfth of your annual property tax and homeowners insurance, your monthly HOA dues, and private mortgage insurance while you owe more than 80% of the purchase price. It does not include closing costs, points, flood or earthquake coverage, utilities or maintenance.
Three usual reasons. Your lender knows the actual tax assessment and insurance quote for the specific property rather than an estimate. They may collect escrow reserves at closing, which changes the first year. And their rate is priced to your credit score, loan type and points, which this calculator does not model.
Private mortgage insurance is required when your loan is above 80% of the home's value at closing. Under the Homeowners Protection Act it must be cancelled automatically once your balance reaches 78% of the original value on the original payment schedule, and you can usually request cancellation at 80%. This calculator uses the automatic 78% point, so it errs toward the higher cost.
A 15-year loan costs substantially more each month and substantially less overall, because you are borrowing the money for half as long. Switch the term in the calculator and compare the monthly payment against the total interest — those two figures are the whole trade-off. The right answer depends on whether the higher payment is comfortable in a bad month, not just an average one.
It always lowers the monthly payment and the total interest, and above 20% it removes mortgage insurance entirely. Whether it is the best use of the cash is a different question — money in the down payment is money not in an emergency fund or invested elsewhere. The down payment comparison above shows what each level is worth on your numbers.
No, and this is the largest simplification in the estimate. Assessments and premiums generally rise over time, so the later years of the schedule understate what you will actually pay. The principal and interest portion is fixed on a fixed-rate loan; the rest is not.
Buying a home
Amortization ScheduleEvery payment on a loan, principal against interestRelated calculators
This calculator produces an estimate for planning purposes. It is not a loan offer, a rate quote, or financial advice. Your actual payment depends on the property, your lender, your credit and your state.