Mortgage Calculator
Estimate your monthly mortgage payment, total interest, and total cost for any home loan amount, rate, and term.
What is a mortgage calculator?
A mortgage calculator is a tool that estimates your monthly home-loan payment from four numbers: the home price, your down payment, the interest rate, and the loan term. Enter them above and you get the monthly principal-and-interest payment, the total interest you will pay, and the total cost of the loan.
Use it before you talk to a lender, so you walk in knowing what a $400,000 house actually costs per month at today's rates — and how much a bigger down payment, a shorter term, or a quarter-point lower rate would change that number.
What is in a monthly mortgage payment?
The figure this calculator shows is principal and interest (P&I) — the part that repays the loan. Your real monthly housing bill has more in it. Lenders and the IRS call the full amount PITI:
| Component | What it is | Typical amount (U.S.) |
|---|---|---|
| Principal | Repays the amount you borrowed | Rises every month (see amortization below) |
| Interest | What the lender charges on the balance | Falls every month |
| Taxes | Property tax, collected into escrow | About 1% of home value per year on average; from ~0.3% (Hawaii) to over 2% (New Jersey, Illinois) |
| Insurance | Homeowners insurance, also escrowed | Often $1,500–$3,000 a year; far more in hurricane and wildfire zones |
| PMI / MIP | Mortgage insurance if you put down less than 20% | Roughly 0.3%–1.5% of the loan per year |
| HOA dues | If the property is in an association | $0 to several hundred dollars a month |
For the $400,000 example used on this page, the P&I payment is about $2,076. Add roughly $333 a month in property tax (1%), $170 in insurance, and — if the down payment were 10% instead of 20% — $150–$450 in PMI, and the real monthly cost lands between $2,600 and $3,000. Budget on PITI, not on P&I.
15-year vs 20-year vs 30-year: the same loan, three ways
The loan term is the single biggest lever after the rate. Here is a $320,000 loan at 6.75% APR over each common term:
| Term | Monthly P&I | Total interest | Total paid |
|---|---|---|---|
| 30 years | $2,076 | $427,185 | $747,185 |
| 20 years | $2,433 | $263,960 | $583,960 |
| 15 years | $2,832 | $189,708 | $509,708 |
The 15-year loan costs $756 more per month but saves $237,477 in interest — more than half. In practice 15-year loans also carry a lower rate than 30-year loans (typically 0.5–0.75 percentage points less), which widens the gap further. The trade-off is flexibility: a 30-year loan with voluntary extra payments gives you the option to pay it off early without the obligation.
How much difference does the interest rate make?
Rates move daily and lenders quote different numbers to the same borrower. On the same $320,000, 30-year loan:
| Rate | Monthly P&I | Total interest |
|---|---|---|
| 5.50% | $1,817 | $334,093 |
| 6.00% | $1,919 | $370,682 |
| 6.50% | $2,023 | $408,142 |
| 6.75% | $2,076 | $427,185 |
| 7.00% | $2,129 | $446,428 |
| 7.50% | $2,237 | $485,495 |
| 8.00% | $2,348 | $525,297 |
Every quarter-point is worth about $53 a month here, or roughly $19,000 over the life of the loan. That is why it pays to get quotes from at least three lenders and to compare the APR (which includes lender fees) rather than the headline rate alone.
How much house can you afford?
The traditional guideline is the 28/36 rule: keep your full housing payment (PITI) under 28% of gross monthly income, and all debt payments together — housing plus car loans, student loans and credit-card minimums — under 36%.
| Gross annual income | Max housing payment (28%) | Max total debt (36%) |
|---|---|---|
| $75,000 | $1,750 / month | $2,250 / month |
| $100,000 | $2,333 / month | $3,000 / month |
| $150,000 | $3,500 / month | $4,500 / month |
Working backwards at 6.75% over 30 years, a $2,000 P&I budget supports a loan of about $308,000; $2,500 supports about $385,000; $3,000 supports about $463,000 — before taxes and insurance. Lenders will often approve a higher debt-to-income ratio (43% is common, and up to 50% on some programs), but the fact that you can borrow more does not mean the payment will feel comfortable. See our house affordability calculator for a full PITI-based estimate.
Fixed-rate vs adjustable-rate mortgages
This calculator assumes a fixed-rate loan: the rate and the P&I payment never change. An adjustable-rate mortgage (ARM) — a 5/1 or 7/6 ARM, for example — starts with a lower fixed rate for 5 or 7 years and then adjusts every year (or six months) with the market, subject to caps. ARMs can make sense if you expect to sell or refinance before the fixed period ends; if you plan to stay, the certainty of a fixed rate is usually worth its slightly higher price. To model an ARM here, run the fixed period at the intro rate, then re-run the remaining balance at a higher rate.
Loan types at a glance
- Conventional — not government-backed; 3%–20% down; PMI required below 20% down, removable once you reach 20% equity. Loans above the FHFA conforming limit (which changes every year) are jumbo loans with stricter requirements.
- FHA — insured by the Federal Housing Administration; 3.5% down with a 580+ credit score; an upfront mortgage-insurance premium of 1.75% of the loan plus an annual premium (0.55% for most borrowers) that in most cases lasts the life of the loan.
- VA — for eligible service members, veterans and surviving spouses; no down payment, no monthly mortgage insurance, a one-time funding fee (waived for veterans with a service-connected disability).
- USDA — for eligible rural and some suburban areas; no down payment, modest guarantee fees, income limits apply.
Formula
Every fixed-rate mortgage in the United States is priced with the same amortization formula:
M = P × r × (1 + r)n ÷ ((1 + r)n − 1)
- M = monthly payment (principal and interest only)
- P = loan amount = home price − down payment
- r = monthly interest rate = annual rate ÷ 12 ÷ 100 (6.75% → 0.005625)
- n = number of monthly payments = years × 12 (30 years → 360)
The formula finds the one fixed payment that, made 360 times, exactly retires the balance with interest. If the rate is 0%, the payment is simply P ÷ n.
Why the early payments are almost all interest
Interest is charged each month on the remaining balance. In month one you owe the full $320,000, so at 0.5625% per month the interest is $1,800.00 and only $275.51 of the $2,075.51 payment reduces the loan. As the balance falls, the interest portion falls and the principal portion rises — slowly at first, then quickly. That is why the balance on a 30-year loan barely moves in the first few years, why selling within two or three years often means paying closing costs twice for very little equity, and why extra principal payments early on are so powerful.
Worked example
A home priced at $400,000 with a $80,000 (20%) down payment, financed at 6.75% APR over 30 years:
- Loan amount P = $400,000 − $80,000 = $320,000
- Monthly rate r = 6.75 ÷ 12 ÷ 100 = 0.005625
- Number of payments n = 30 × 12 = 360
- (1 + r)n = 1.005625360 ≈ 7.5332
- M = 320,000 × 0.005625 × 7.5332 ÷ (7.5332 − 1) ≈ $2,075.51 per month
- Total paid over 30 years = $2,075.51 × 360 = $747,185
- Total interest = $747,185 − $320,000 = $427,185
Amortization schedule — the first year
| Month | Payment | Interest | Principal | Balance after |
|---|---|---|---|---|
| 1 | $2,075.51 | $1,800.00 | $275.51 | $319,724.49 |
| 2 | $2,075.51 | $1,798.45 | $277.06 | $319,447.42 |
| 3 | $2,075.51 | $1,796.89 | $278.62 | $319,168.80 |
| 4 | $2,075.51 | $1,795.32 | $280.19 | $318,888.61 |
| 5 | $2,075.51 | $1,793.75 | $281.77 | $318,606.85 |
| 6 | $2,075.51 | $1,792.16 | $283.35 | $318,323.49 |
| 7 | $2,075.51 | $1,790.57 | $284.94 | $318,038.55 |
| 8 | $2,075.51 | $1,788.97 | $286.55 | $317,752.00 |
| 9 | $2,075.51 | $1,787.36 | $288.16 | $317,463.84 |
| 10 | $2,075.51 | $1,785.73 | $289.78 | $317,174.06 |
| 11 | $2,075.51 | $1,784.10 | $291.41 | $316,882.66 |
| 12 | $2,075.51 | $1,782.46 | $293.05 | $316,589.61 |
After a full year of payments totalling $24,906, the balance has dropped by just $3,410 — 86% of the first year went to interest.
Where the loan stands at each five-year mark
| End of year | Remaining balance | Principal paid so far | Interest paid so far |
|---|---|---|---|
| 1 | $316,590 | $3,410 | $21,496 |
| 5 | $300,402 | $19,598 | $104,933 |
| 10 | $272,963 | $47,037 | $202,025 |
| 15 | $234,545 | $85,455 | $288,138 |
| 20 | $180,756 | $139,244 | $358,879 |
| 25 | $105,445 | $214,555 | $408,099 |
| 30 | $0 | $320,000 | $427,185 |
The halfway point in time (year 15) is nowhere near the halfway point in payoff: only 27% of the principal has been repaid. You cross 50% of the balance in year 21.
How to use this calculator
- Enter the full purchase price of the home.
- Enter your down payment in dollars. 20% avoids PMI on a conventional loan; 3%–10% is common for first-time buyers and 3.5% is the FHA minimum.
- Enter the interest rate your lender quoted. If you are still shopping, try 6%, 6.5% and 7% to see how sensitive the payment is.
- Enter the loan term in years — 30 is by far the most common in the U.S.; 15 and 20 are the usual alternatives.
- Read the monthly P&I payment, loan amount, total interest and total cost. The results update as you type.
Remember that the payment shown is principal and interest only. Add property tax, homeowners insurance, mortgage insurance (if under 20% down) and any HOA dues to get your true monthly housing cost.
Paying it off faster: extra payments and biweekly plans
Because interest is charged on the balance, any extra dollar you send is applied to principal and stops earning interest for the lender for the rest of the loan. On the $320,000, 6.75%, 30-year example:
| Extra principal per month | Paid off in | Total interest | Interest saved |
|---|---|---|---|
| $0 | 30 years | $427,185 | — |
| $100 | 26 years 2 months | $361,337 | $65,848 |
| $200 | 23 years 4 months | $315,107 | $112,078 |
| $500 | 17 years 10 months | $231,115 | $196,070 |
A biweekly payment plan (half a payment every two weeks) works the same way: 26 half-payments equal 13 full payments a year, so it is effectively one extra payment annually. On this loan that pays it off in 24 years and saves about $101,000 of interest. You do not need a lender's paid biweekly program to get this — just add one-twelfth of your payment to principal each month. Always mark extra amounts "apply to principal" and check the loan has no prepayment penalty.
Discount points: paying for a lower rate
One point costs 1% of the loan ($3,200 here) and typically lowers the rate by about 0.25 percentage points. Going from 6.75% to 6.50% saves $52.90 a month, so the point pays for itself in about 60 months. Points make sense if you will keep the loan well past the break-even; if you might sell or refinance within five years, they do not.
Refinancing: the break-even test
Refinancing replaces your loan with a new one, usually to get a lower rate, and costs closing fees of roughly 2%–5% of the loan. The test is simple: divide the closing costs by the monthly saving. A $300,000 balance refinanced from 7.25% to 6.25% saves about $199 a month; with $6,000 in costs, you break even in 30 months. If you will stay longer than that, it pays. Run both loans through this calculator and compare the total interest too — restarting a 30-year clock can cost more overall even when the monthly payment drops.
Related tools
- House affordability calculator — how much home your income supports, PITI included
- Down payment calculator — how much to save and how it changes your payment
- Property tax calculator — estimate the "T" in PITI for your county
- Rent vs. buy calculator — whether buying beats renting in your market
Frequently asked questions
What is included in my monthly mortgage payment?
A typical U.S. mortgage payment has four parts (PITI): principal, interest, property taxes and homeowners insurance. If you put down less than 20%, private mortgage insurance (PMI) is usually added; FHA loans carry a similar monthly mortgage-insurance premium (MIP). Condos and many subdivisions add HOA dues. This calculator shows principal and interest only — add the rest for your true monthly housing cost.
How much house can I afford?
The 28/36 rule is the classic guideline: keep your full housing payment (PITI) under 28% of gross monthly income and all debt payments under 36%. On a $100,000 salary that is $2,333 a month for housing, which at 6.75% over 30 years supports a loan of roughly $360,000 before taxes and insurance. Lenders often approve up to a 43%–50% debt-to-income ratio, but that leaves little room for savings, childcare or a job change.
Should I choose a 15-year or 30-year mortgage?
On the same $320,000 at 6.75%, the 15-year payment is $2,832 versus $2,076 — about 36% higher — but total interest falls from $427,185 to $189,708. Fifteen-year loans also usually carry a lower rate. Choose the 15-year if the payment fits comfortably; choose the 30-year if you want flexibility, and make extra principal payments when you can — that gets you most of the interest savings without the obligation.
What interest rate will I actually get?
Your rate depends on your credit score (the biggest factor — 740+ gets the best pricing), down payment size, loan type (conventional, FHA, VA, jumbo), property type, and whether you pay discount points, on top of the day's market rates. Advertised rates assume excellent credit and 20% down. Get Loan Estimates from at least three lenders on the same day and compare the APR, which includes lender fees, not just the rate.
What is PMI and how do I avoid it?
Private mortgage insurance protects the lender if you default. On conventional loans it is required when your down payment is below 20%, and typically costs 0.3%–1.5% of the loan amount per year — $150 to $450 a month on a $360,000 loan. Avoid it with 20% down, or remove it later: you can request cancellation once your balance reaches 80% of the original value, and lenders must cancel it automatically at 78% under the Homeowners Protection Act.
What is the difference between interest rate and APR?
The interest rate is what you pay on the balance. The APR (annual percentage rate) also folds in lender fees, points and some closing costs, expressed as a yearly rate — so it is always equal to or higher than the rate and is the better number for comparing offers. This calculator uses the plain interest rate, because that is what determines the monthly payment.
Does paying extra on my mortgage really help?
Yes, and more than most people expect. Every extra dollar goes straight to principal, so it stops accruing interest for the remaining life of the loan. An extra $200 a month on a $320,000, 6.75%, 30-year loan cuts the payoff to 23 years 4 months and saves about $112,000 in interest. Make sure extra payments are applied to principal, not to next month's payment, and confirm there is no prepayment penalty.
What are closing costs on a mortgage?
Closing costs are the fees to originate and record the loan — appraisal, title insurance, lender origination fees, prepaid taxes and insurance, recording fees — and typically total 2%–5% of the loan amount, so $6,400–$16,000 on a $320,000 loan. They are paid at closing, separate from the down payment. Sellers sometimes agree to pay part of them ("seller concessions"), and some lenders offer no-closing-cost loans in exchange for a higher rate.
Can I use this calculator for an adjustable-rate mortgage (ARM)?
Only for the fixed period. Enter the introductory rate and the full term to see the starting payment. When the loan adjusts, the payment is recalculated on the remaining balance, the new rate and the remaining term — so run a second calculation with the balance at the adjustment date (from the amortization table) as the loan amount, the higher rate, and the years left.
Why is my first payment almost all interest?
Because interest is charged on the outstanding balance, and at the start the balance is the whole loan. On $320,000 at 6.75%, month one is $1,800 of interest and only $275.51 of principal. As the balance shrinks the split shifts, but slowly: it takes until year 21 to have repaid half the loan on a 30-year schedule.