Mortgage Calculator
Calculate precise monthly payments including principal, amortized interest, local property taxes, homeowner's insurance, and PMI. Client-side evaluation with a full amortization schedule.
Amortization Schedule
Yearly progression of loan reduction, capital equity accrual, and diminishing interest load.
Mathematical Formula & Methodology
Standard residential amortization uses an ordinary annuity present value model where the periodic payment is calibrated so the remaining debt equals exactly zero at term maturity:
Lender disclosures are governed by the Truth in Lending Act (Regulation Z, 12 CFR Part 1026) and will include fees this estimate leaves out. Escrow amounts are held constant; real property tax and insurance bills usually rise over time.
Related Calculators
How this calculator works
This calculator uses the standard fixed-rate amortization formula for principal and interest, then adds property tax, home insurance, HOA dues and PMI so you see the full housing cost — not only the loan payment. The loan amount is the home price minus your down payment. PMI is estimated at your chosen rate (0.50% of the loan per year by default) only when you put down less than 20%, and it drops off automatically once the balance reaches 78% of the original home value. Extra principal payments are applied every month and shorten the loan.
By Suhaib Hassan · Formula verified 24 Sep 2026; examples re-run 17 Oct 2026 (extra-payment and escrow examples added) · How CalculatePilot verifies formulas →
What goes into a monthly mortgage payment
Most lenders quote PITI: principal, interest, taxes, and insurance.
- Principal — the portion of each payment that reduces the outstanding balance.
- Interest — the cost of borrowing. Early payments on a 30-year loan are mostly interest.
- Property tax — county assessments, usually collected monthly into escrow.
- Homeowners insurance — hazard coverage, often escrowed with taxes.
- PMI — required on conventional loans below 20% down, typically 0.3–1.5% of the loan per year.
- HOA dues — set by the association, not the lender.
Biweekly payment power: 26 half-payments a year equal 13 full payments and can shorten a 30-year loan by about 4–6 years. You can model the same effect by entering one-twelfth of a payment as extra principal.
How the interest rate changes the payment
Principal and interest on a $320,000 loan (a $400,000 home with 20% down), 30-year fixed:
| Rate | Monthly P&I | Total interest |
|---|---|---|
| 5.5% | $1,816.92 | $334,093 |
| 6.0% | $1,918.56 | $370,682 |
| 6.5% | $2,022.62 | $408,142 |
| 7.0% | $2,128.97 | $446,428 |
| 7.5% | $2,237.49 | $485,495 |
Each 0.5 percentage point adds roughly $100 to $110 a month on this loan, and about $37,000 to $39,000 in interest over 30 years.
15-year vs 30-year mortgage
The same $320,000 loan. A 15-year loan usually carries a lower rate; the 5.75% below is an example, not a quote.
| Loan | Monthly P&I | Total interest |
|---|---|---|
| 30-year at 6.5% | $2,022.62 | $408,142 |
| 15-year at 5.75% | $2,657.31 | $158,316 |
The 15-year costs $634.69 more each month and saves about $249,826 in interest. Enter both in the calculator to compare with your own rates.
What PMI adds at different down payments
On a $400,000 home at 6.5% with PMI at 0.5% of the loan a year, and PMI ending when the scheduled balance reaches 78% of the original value:
| Down payment | Loan | Monthly PMI | PMI ends after | PMI paid |
|---|---|---|---|---|
| 5% | $380,000 | $158.33 | 135 months | about $21,375 |
| 10% | $360,000 | $150.00 | 109 months | about $16,350 |
| 15% | $340,000 | $141.67 | 75 months | about $10,625 |
| 20% | $320,000 | none | n/a | $0 |
Under the federal Homeowners Protection Act, you can ask your servicer to cancel PMI when the scheduled balance reaches 80% of the original value (with a good payment record and no junior liens), it ends automatically at 78% if you are current, and it must end after the midpoint of the loan term. FHA and VA loans follow different rules. Extra principal payments bring the date forward.
What biweekly payments save
Paying half the monthly payment every two weeks makes 26 half-payments, or 13 full payments, a year. On the $320,000 loan at 6.5%, this pays the loan off in about 24.2 years instead of 30 and cuts total interest from $408,142 to about $314,146, saving about $93,996. Confirm your servicer applies each half-payment promptly and does not charge a fee.
Stress-testing a 5/1 ARM
Suppose a 5/1 ARM on the same $320,000 starts at 5.75%, then resets to 7.75% after year 5 (the calculator models one reset). Payment in the first five years: $1,867.43. The balance after 60 payments is about $296,839, and the payment then rises to about $2,242.11, which is $374.68 more. Compared with a 6.5% fixed loan ($2,022.62), the ARM is cheaper for five years but would cost more afterwards in this scenario. Test your own reset rate in the ARM option.
Worked example with the calculator's default inputs
A $450,000 home with 20% down ($90,000), a $360,000 30-year loan at 6.75%, property tax of $4,200 a year and insurance of $1,400 a year:
| Item | Monthly |
|---|---|
| Principal and interest | $2,334.95 |
| Property tax | $350.00 |
| Homeowners insurance | $116.67 |
| Total (PITI) | $2,801.62 |
Total interest over 30 years is about $480,583. No PMI applies at 20% down.
One-time, yearly and monthly extra payments compared
Extra principal on a $320,000, 30-year loan at 6.5% (base: 360 payments, $408,142 interest):
| Extra payment | Payoff time | Interest saved |
|---|---|---|
| $10,000 once, in month 1 | 329 months (27.4 yrs) | $53,943 |
| $10,000 once, in month 60 | 337 months (28.1 yrs) | $37,546 |
| $2,000 every year | 293 months (24.4 yrs) | $88,832 |
| $200 every month | 281 months (23.4 yrs) | $105,429 |
The earlier the extra goes in, the more it saves. The Extra Principal Payment box takes a monthly amount, so for a yearly amount enter one-twelfth of it (about $167 for $2,000 a year, which saves about $92,296). It does not model a single lump sum.
Why a fixed-rate payment can still rise
Principal and interest stay fixed, but taxes and insurance usually do not. Starting from $4,200 of tax and $1,400 of insurance, and assuming tax grows 3% a year and insurance 5% a year (assumptions, not forecasts):
| Year | Tax + insurance per month |
|---|---|
| 1 | $466.67 |
| 5 | $535.74 |
| 10 | $637.66 |
| 20 | $908.54 |
The calculator holds these constant, so treat your result as the first-year payment.
Costs the calculator leaves out
- Closing costs: paid once at purchase. Your lender's Loan Estimate lists them.
- Maintenance and repairs: a common rule of thumb is to budget about 1% of the home's value a year.
- Utilities, moving and furnishing.
Before you pay the mortgage off early
- Prepayment penalty: check your loan documents; some loans charge one for early payoff.
- Opportunity cost and liquidity: money in the house is harder to reach in an emergency, and it may earn more elsewhere. See extra payments vs investing.
- Tax deduction: mortgage interest is deductible only if you itemize, and under IRS Publication 936 (2025 edition) the limit for debt taken on after 15 December 2017 is $750,000 ($375,000 if married filing separately). Check the rules for the year you file.
Frequently asked questions
How is a monthly mortgage payment calculated?
Fixed-rate amortization for principal and interest, then monthly tax and insurance. Estimate only — not a lender quote.
Does this include PMI, HOA fees, or closing costs?
HOA is optional. Estimated PMI appears below 20% down. Closing costs are not included.
How much house can I afford?
A common starting point is 28–36% of gross income. Use the House Affordability Calculator.
Should I choose a 15-year or 30-year mortgage?
15-year usually costs less interest and more per month. 30-year keeps the payment lower. The 15-Year Fixed card above shows how much interest you'd save at your inputs.
Does a larger down payment lower my monthly payment?
Yes. It reduces the loan amount and often removes PMI at 20% down.
Are these figures a formal loan offer?
No. Confirm rates and fees with a lender quote.
Should I pay extra on my mortgage or invest that money instead?
On a $400,000 loan at 7%, $300/month extra saves $168,391 in interest and pays off 7.8 years early — a guaranteed 7% return. Investing the same $300/month at 8% would grow to ~$450,389 over the same period. See the full extra-payments-vs-investing breakdown for the math.
When exactly does PMI come off my loan?
By federal law, PMI automatically ends at 78% of your home's original value; you can request removal yourself at 80%. This calculator drops PMI at the 78% point, and extra payments bring that date forward.
How much does a 0.5% higher mortgage rate cost?
On a $320,000 30-year loan, going from 6.5% to 7.0% raises the monthly principal and interest from $2,022.62 to $2,128.97, about $106 more, and total interest by about $38,286.
How much interest does a 15-year mortgage save?
On a $320,000 loan, a 15-year at 5.75% costs $2,657.31 a month and $158,316 in total interest, versus $2,022.62 and $408,142 for a 30-year at 6.5%, a saving of about $249,826 (example rates).
How much PMI will I pay with 5% down?
On a $400,000 home at 6.5% with PMI at 0.5% a year, about $158 a month, ending after about 135 months when the scheduled balance reaches 78% of the original value, for roughly $21,375 in total.
Do biweekly mortgage payments really save money?
Yes, because 26 half-payments equal 13 full payments a year. On a $320,000 loan at 6.5% this pays off in about 24.2 years and saves about $93,996 in interest.
What happens to a 5/1 ARM payment after five years?
It resets to the then-current rate. In our example, 5.75% rising to 7.75% on a $320,000 loan lifts the payment from $1,867.43 to about $2,242.11.
Is it better to make a one-time extra payment or extra monthly payments?
Earlier and more frequent extra principal saves more. On a $320,000, 6.5% loan, $10,000 once in month 1 saves about $53,943 in interest, while $200 every month saves about $105,429.
How much does a yearly extra mortgage payment save?
On a $320,000 loan at 6.5%, $2,000 extra each year pays the loan off in about 24.4 years and saves about $88,832 in interest.
Why does my mortgage payment go up when my rate is fixed?
Principal and interest stay the same, but property tax and homeowners insurance usually rise. If tax grows 3% and insurance 5% a year, $466.67 a month in year 1 becomes about $637.66 in year 10.
Can I deduct mortgage interest?
Only if you itemize deductions. IRS Publication 936 (2025) caps the debt at $750,000 ($375,000 if married filing separately) for loans taken after 15 December 2017.
What costs does a mortgage calculator not include?
Closing costs, maintenance and repairs (a common rule of thumb is about 1% of home value a year), utilities, moving and furnishing. Ask your lender for a Loan Estimate for closing costs.
Next calculation, in order
1. Affordability · 2. Down payment · 3. Amortization · 4. Refinance · UK repayment · Extra payments vs investing