Estimate your monthly principal & interest payment, total interest over the life of the loan, and view a full amortization schedule. Everything runs in your browser.
How the Mortgage Calculator works
This calculator solves the standard amortizing-loan formula to turn your home loan amount, interest rate, and term into a fixed monthly principal-and-interest (P&I) payment. It does not include property taxes or homeowners insurance - it answers the question "what is the loan portion of my payment?" Your lender adds the rest to build your full PITI.The formula is:
M = P x [ i(1+i)n ] / [ (1+i)n - 1 ]
- M = monthly principal & interest payment
- P = principal (the amount you actually borrow = home price minus down payment)
- i = monthly interest rate = annual rate / 12 (so 6.5% becomes 0.065 / 12 = 0.00541667)
- n = total number of monthly payments = years x 12 (30 years = 360)
Internally, the tool runs these steps:
- Converts your annual rate to a monthly decimal rate (i).
- Converts your term in years to a payment count (n).
- Plugs P, i, and n into the formula to get the fixed monthly P&I.
- Multiplies that payment by n to get total paid, then subtracts P to get lifetime interest.
- Builds an amortization schedule: each month it charges interest on the current balance (balance x i), applies the rest of the payment to principal, and reduces the balance.
Edge cases it handles: a 0% rate falls back to simple division (P / n) because the standard formula divides by zero when i = 0. It assumes a fixed rate for the full term, fully amortizing to a $0 balance - so it does not model adjustable rates, interest-only periods, or balloons. Because rounding each payment to the cent can leave a tiny residual, the final scheduled payment is adjusted by a few cents so the balance lands exactly at zero.
]]>Example calculation
Here are three fully worked home-loan scenarios so you can see how loan size, rate, and term move the payment and the lifetime interest. Every figure below is computed with the formula above and rounded to the cent.Example 1 - $400,000 loan, 6.5%, 30 years. Monthly i = 0.065 / 12 = 0.00541667; n = 360. The P&I payment is $2,528.27. Over 360 months you pay $910,177.95, of which $510,177.95 is interest - more than the amount you borrowed. The very first payment is mostly interest: $2,166.67 interest and only $361.61 toward principal.
Example 2 - $250,000 loan, 7.0%, 30 years. Here i = 0.00583333 and n = 360. The P&I payment is $1,663.26, total paid is $598,772.25, and lifetime interest is $348,772.25. Note this is P&I only; with roughly $286/mo property tax and $150/mo insurance, the real housing cost (PITI) is closer to $2,100 - about 26% above the bare loan payment.
Example 3 - $600,000 loan, 6.75%, 30 years (jumbo range). With i = 0.005625 and n = 360, the payment is $3,891.59, total paid is $1,400,971.89, and lifetime interest is $800,971.89. This loan likely exceeds the conforming limit in most counties, so it would carry jumbo underwriting on top of these numbers.
| Scenario | Loan | Rate | Term | Monthly P&I | Total interest |
|---|---|---|---|---|---|
| Example 1 | $400,000 | 6.50% | 30 yr | $2,528.27 | $510,177.95 |
| Example 2 | $250,000 | 7.00% | 30 yr | $1,663.26 | $348,772.25 |
| Example 3 | $600,000 | 6.75% | 30 yr | $3,891.59 | $800,971.89 |
The takeaway: the monthly payment scales roughly with loan size, but total interest scales brutally with both balance and rate - a $600k loan at 6.75% costs over $800k in interest alone across 30 years, and that is before a single dollar of taxes, insurance, or PMI.
]]>Tips for using the Mortgage Calculator
- Remember this tool shows P&I only - budget for the full PITI. Add property tax (commonly 0.3%-2.2% of home value per year, wildly state-dependent), homeowners insurance, PMI if you put under 20% down, and any HOA dues before deciding what you can afford.
- PMI is not permanent. Once you reach 20% equity you can request cancellation, and at 22% equity by the original schedule the lender must drop it automatically - so a payment that feels tight at 10% down can ease by $100-$200/mo within a few years.
- Compare points on dollars, not vibes. One discount point costs 1% of the loan and typically shaves about 0.25% off the rate. On a $400,000 loan at 6.5%, buying down to 6.25% costs $4,000 and saves about $65.40/mo, so you break even at roughly 61 months - only worth it if you will keep the loan past 5 years.
- The rate you are quoted is for principal and interest, but the APR you see on the disclosure folds in points and lender fees - always compare home loans by APR, not the headline rate, to catch hidden costs.
- Early payments are almost all interest. On the $400k/6.5% loan, your first payment puts only $361.61 toward principal; principal does not exceed interest until around payment 233 (year 19.4). This is why selling or refinancing early means you have built very little equity.
- Get the loan amount right: it is home price minus down payment, not the home price. Run the purchase price through the Down Payment Calculator first so you feed this tool the actual financed amount.
- Escrow can make your 'fixed' payment rise. Lenders collect tax and insurance monthly into an escrow account; when your county reassesses or your insurer raises premiums, your total payment increases even though the P&I never changes.
- Watch the conforming loan limit. Loans above the annual conforming cap become jumbo loans, which often carry stricter credit, reserve, and down-payment requirements - sometimes at a higher rate - so a price just over the line can cost more than it looks.
- Use the 15-vs-30 trade-off deliberately: on a $400k loan, a 15-year term can cut lifetime interest by more than 60%, but only commit if the higher payment still leaves room for your emergency fund and retirement contributions.
- Do not let a lender's pre-approval set your budget. Banks qualify you on the back-end DTI ceiling; back into a comfortable PITI from your take-home pay, then solve for the loan that fits it - approval is not the same as affordable.
P&I vs PITI: what this calculator does and does not include
This tool calculates P&I (principal and interest), but your actual monthly housing bill is PITI - principal, interest, taxes, and insurance - and often more. Confusing the two is the single biggest reason home buyers feel blindsided at closing.
Here is how the layers stack on a real $250,000 loan at 7% for 30 years:
| Component | Monthly | What it is |
|---|---|---|
| Principal & Interest | $1,663.26 | The loan payment this tool computes |
| Property tax | ~$286 | County tax, escrowed (varies hugely by state) |
| Homeowners insurance | ~$150 | Required hazard coverage, escrowed |
| PMI (if <20% down) | ~$125 | Drops off near 20-22% equity |
| HOA dues | $0-$500+ | Condos and planned communities only |
In this example, P&I is only about 75% of the PITI total - and that is before HOA. Always add the other lines before judging affordability. To pressure-test the whole payment against your income, run the figure through the debt-to-income ratio calculator.
15-year vs 30-year: the trade-off in dollars
A 15-year mortgage roughly doubles the principal you pay each month but can cut lifetime interest by more than 60%, because you borrow the money for half as long and usually at a lower rate.
Compare a $400,000 loan two ways - a 30-year at 6.5% and a 15-year at 5.75% (15-year rates are typically lower):
| Term | Rate | Monthly P&I | Total interest |
|---|---|---|---|
| 30 years | 6.50% | $2,528.27 | $510,177.95 |
| 15 years | 5.75% | $3,321.64 | $197,895.26 |
The 15-year costs $793.37 more per month but saves $312,282.69 in interest. The catch: that higher payment is mandatory every month, with no flexibility in a bad year. Many buyers split the difference - take the 30-year for its lower required payment, then send extra voluntarily. See exactly what that does with the extra payment mortgage calculator. For the full side-by-side breakdown, read our guide on 15-year vs 30-year mortgages.
Why your early payments are almost all interest
On a fixed mortgage, interest is charged on the remaining balance each month, so when the balance is highest - at the start - interest eats almost the entire payment and principal grows slowly. This is called front-loaded amortization, and it surprises most first-time buyers.
On the $400,000 / 6.5% / 30-year loan, the contrast between the first and last payment is stark:
| Payment | Goes to interest | Goes to principal |
|---|---|---|
| Month 1 | $2,166.67 | $361.61 |
| Month 360 | $13.62 | $2,514.65 |
The payment is identical ($2,528.27) every month, but the split flips completely. The principal portion does not overtake the interest portion until around payment 233 (year 19.4), so in the first decade-plus you build equity painfully slowly. This is why selling or refinancing early leaves you with little to show for years of payments - and why any extra dollar applied to principal early is so powerful, since it removes interest from every future month. To understand the mechanics of interest accrual in general, see how loan interest works.
How to calculate a mortgage payment in Excel or by hand
In any spreadsheet, the function is =PMT(rate, nper, pv) - and the result will match this calculator to the cent.
The trick is the arguments: the rate must be monthly (annual / 12), nper is months (years x 12), and pv is the loan amount entered as a negative number so the payment comes back positive.
- Excel / Google Sheets:
=PMT(0.065/12, 360, -400000)returns $2,528.27. - For a 15-year loan:
=PMT(0.0575/12, 180, -400000)returns $3,321.64.
To see how much of any single payment is interest versus principal, use =IPMT(rate, period, nper, pv) and =PPMT(rate, period, nper, pv) - for example =PPMT(0.065/12, 1, 360, -400000) returns $361.61, the principal in month one.
By hand, the algebra is: compute (1 + i) raised to the n power, then M = P x i x that value, divided by (that value minus 1). It is tedious because of the exponent, but the formula is identical to what the tool runs. For a deeper walkthrough, see how to calculate a mortgage payment.
Common mistakes when estimating a mortgage
The most expensive mistakes are confusing the loan amount with the home price and judging affordability on P&I alone. Here are the errors we see most:
- Entering the home price instead of the loan. You finance price minus down payment. Putting the full price in inflates every number.
- Forgetting taxes and insurance. PITI can run 20-30% above P&I. A payment that looks affordable here may not be once escrow is added.
- Ignoring PMI. Under 20% down adds a monthly premium that this tool does not show - and it can be $100-$300/mo.
- Comparing rate to rate instead of APR to APR. Points and fees hide in APR; a 'lower rate' with three points can cost more.
- Treating pre-approval as a budget. Lenders approve you to the edge of their DTI limit, not to a comfortable number.
- Assuming the payment is fixed forever. P&I is fixed on a fixed-rate loan, but escrowed taxes and insurance drift upward over time.
Before you settle on a price, figure out the down payment that avoids PMI using the down payment calculator.
Is your payment reasonable? Affordability benchmarks
The classic guideline is the 28/36 rule: spend no more than 28% of gross monthly income on PITI, and no more than 36% on all debt combined. These are ceilings, not targets - many financially comfortable buyers stay well below them.
For a household earning $90,000 gross ($7,500/mo), the limits work out to:
| Limit | Percent | Monthly cap |
|---|---|---|
| Front-end (housing/PITI) | 28% | $2,100 |
| Back-end (all debt) | 36% | $2,700 |
So this household should aim to keep total housing under about $2,100/mo and total debt payments under $2,700/mo. Note these caps apply to PITI, not the bare P&I this tool shows - so back the taxes and insurance out before comparing. Lenders may approve higher back-end DTIs (often up to 43-50% on qualifying loans), but approval is not the same as affordable. Verify your numbers with the debt-to-income ratio calculator and the loan affordability calculator.
Conforming vs jumbo, points, and escrow explained
Three terms shape your real cost beyond the formula: the conforming limit, discount points, and escrow.
Conforming vs jumbo: loans at or below the annual conforming limit set by federal housing regulators can be sold to Fannie Mae and Freddie Mac, which keeps rates and underwriting standardized. Cross that limit and you have a jumbo loan - typically requiring stronger credit, larger reserves, and sometimes a bigger down payment. A purchase price just over the line can therefore cost more than one just under it, which is why the $600,000 loan in Example 3 likely lands in jumbo territory.
Discount points: each point is a prepaid 1% of the loan that buys down your rate by roughly 0.25%. On $400,000, one point ($4,000) taking 6.5% to 6.25% saves about $65.40/mo - a ~61-month break-even. Buy points only if you will keep the loan well past that.
Escrow: most lenders bundle property tax and insurance into your monthly payment, hold the money in an escrow account, and pay those bills for you. It smooths big annual bills into monthly chunks - but it also means your total payment changes whenever taxes or premiums change. If you finance closing costs or points, run the new loan amount back through this calculator to see the true monthly impact.
Mortgage Payment Quick Reference: Monthly P&I by Loan Amount and Rate (30-Year)
Your monthly payment depends mostly on three things: the loan amount, the interest rate, and the term. The table below shows monthly principal and interest (P&I) for common 30-year loan amounts at four rates - every figure recomputed with the standard amortization formula. Remember this is P&I only; lenders add property tax, homeowners insurance, PMI (under 20% down), and any HOA dues to reach your true monthly cost (PITI). As a rule of thumb, each 1% rate increase adds roughly $66 per month for every $100,000 borrowed.
| Loan amount | 6.0% | 6.5% | 7.0% | 7.5% |
|---|---|---|---|---|
| $200,000 | $1,199 | $1,264 | $1,331 | $1,398 |
| $300,000 | $1,799 | $1,896 | $1,996 | $2,098 |
| $400,000 | $2,398 | $2,528 | $2,661 | $2,797 |
| $500,000 | $2,998 | $3,160 | $3,327 | $3,496 |
Related on this site
Down Payment Calculator · Mortgage Refinance Calculator · Biweekly Mortgage Calculator · Loan Affordability Calculator · Debt-to-Income Ratio Calculator · Interest-Only Mortgage Calculator
For a related deep dive, see CFPB owning a home guide.
Mortgage Calculator — frequently asked questions
- Does this include taxes and insurance?
- No — this is principal and interest only. Property tax, insurance and PMI/HOA vary by location and are added by your lender.
- How do I pay less interest?
- A shorter term, larger down payment, lower rate, or extra principal each month all cut total interest significantly.
- What credit score do I need for the best mortgage rate?
- Generally 740+ unlocks the lowest advertised rates; lower scores still qualify but at higher rates, which this calculator lets you compare.
- Should I choose a 15 or 30-year mortgage?
- A 30-year keeps payments low and flexible; a 15-year builds equity faster and costs far less interest. Compare both here.
- How much is the monthly payment on a $400,000 mortgage at 7% for 30 years?
- About $2,661.21 a month in principal and interest. Using the standard formula on a $400,000 loan at 7% over 360 months, you would repay roughly $958,036 total, of which about $558,036 is interest. Remember this is P&I only - your lender adds property tax, homeowners insurance, and PMI (if you put under 20% down) on top. Run your own numbers in the <a href="/mortgage-calculator/">mortgage calculator</a>.
- What is the full monthly PITI on a $400,000 home with 10% down?
- Roughly $2,972 a month once you add taxes and insurance. A $400,000 home with 10% down is a $360,000 loan; at 6.5% over 30 years that is $2,275.44 P&I. Add about $367 property tax (1.1%/yr), $150 homeowners insurance, and $180 PMI (0.6%/yr) and you reach about $2,972. P&I is only about 77% of what you actually pay each month.
- How much interest do you pay on a $300,000 mortgage over 30 years at 7%?
- About $418,527 in interest - more than the loan itself. At 7% over 360 months the payment is $1,995.91, so you repay roughly $718,527 total on a $300,000 loan. Cutting the term to 15 years raises the payment to $2,696.48 but drops total interest to about $185,367, saving roughly $233,000. Compare both terms in the <a href="/mortgage-calculator/">mortgage calculator</a>.
- How much does 1 discount point lower my mortgage payment on a $400,000 loan?
- One point typically costs $4,000 and shaves roughly 0.25% off the rate, saving about $67 a month. Moving a $400,000 loan from 7% to 6.75% cuts P&I from $2,661.21 to $2,594.39 - a $66.82 monthly saving. You recover the $4,000 cost in about 60 months (5 years), so points pay off only if you keep the loan past that break-even point.
- Is it worth paying 2 points to drop the rate on a $300,000 mortgage?
- Only if you stay in the home past the roughly 5-year break-even. Two points on a $300,000 loan cost $6,000 and might lower the rate from 6.5% to 6.0%, cutting P&I from $1,896.20 to $1,798.65 - a $97.55 monthly saving. Dividing $6,000 by $97.55 gives about 62 months. Sell or refinance before then and you lose money on the points.
- How much more is a 15-year mortgage per month than a 30-year on a $400,000 loan?
- About $956 more per month, but you save roughly $283,000 in interest. At 6.5%, a $400,000 loan costs $2,528.27/mo over 30 years ($510,178 interest) versus $3,484.43/mo over 15 years ($227,197 interest). The 15-year payment is about 38% higher but total interest is less than half. Weigh cash-flow flexibility against the savings in the <a href="/mortgage-calculator/">mortgage calculator</a>.
- How much of my first mortgage payment goes to principal on a $400,000 loan at 7%?
- Only about $327.88 - the other $2,333.33 is pure interest. On a $400,000 loan at 7% over 30 years, the $2,661.21 payment is split so that month one is about 88% interest. This is front-loaded amortization: early payments barely dent the balance, and principal does not pull ahead of interest until past payment 240.
- When does principal exceed interest on a 30-year mortgage?
- Usually around year 19 to 20 on a typical 30-year loan. On a $300,000 loan at 7%, the principal portion first overtakes the interest portion at payment 242 (year 20.2). On a $400,000 loan at 6.5% it crosses at payment 233 (year 19.4). Higher rates push the crossover later. This is why selling early means you have built little equity through payments alone.
- How do I calculate a mortgage payment in Excel?
- Use =PMT(rate/12, years*12, -loan). For a $400,000 loan at 7% over 30 years, enter =PMT(0.07/12, 360, -400000), which returns $2,661.21. Divide the annual rate by 12 for the monthly rate, multiply years by 12 for the number of payments, and make the loan amount negative so the result shows as a positive payment. Add taxes and insurance separately for full PITI.
- How much does PMI cost per month on a $300,000 loan?
- Typically $125 to $250 a month, depending on the rate your lender uses. PMI usually runs 0.5% to 1% of the loan per year: on $300,000 that is $1,500 to $3,000 annually, or about $125 to $250 monthly. It is required when you put down less than 20% and generally drops off once you reach 20% equity. Putting 20% down avoids it entirely.
- What is escrow on a mortgage and how much does it add?
- Escrow is a lender-held account that collects your property tax and insurance with each payment, often adding several hundred dollars a month. On a $350,000 home, expect roughly $321/mo for property tax (about 1.1%/yr) plus $142/mo for homeowners insurance - about $463 added on top of P&I. Lenders may also keep a small cushion, so your total payment is meaningfully higher than the calculator's P&I figure.
- What is the difference between a conforming and a jumbo mortgage in 2025?
- A conforming loan stays within the 2025 baseline limit of $806,500; a jumbo loan exceeds it. Conforming loans can be sold to Fannie Mae and Freddie Mac, so they usually carry lower rates and easier underwriting. Jumbo loans (above $806,500, or above $1,209,750 in high-cost areas) often require stronger credit, bigger down payments, and more reserves. The monthly-payment math is identical - only qualifying differs.
- How much does a 1% higher mortgage rate cost over 30 years on a $400,000 loan?
- About $94,683 more in total payments. At 6% a $400,000 loan costs $2,398.20/mo and $863,353 over 30 years; at 7% it is $2,661.21/mo and $958,036 total. That single percentage point adds $263 to every monthly payment. Even a small rate difference compounds dramatically over 360 payments, which is why shopping multiple lenders matters.
- How much equity have I built after 5 years on a $300,000 mortgage at 7%?
- Only about $17,605 in equity from payments alone. On a $300,000 loan at 7% over 30 years, after 60 payments of $1,995.91 the balance is still about $282,395. Because amortization is front-loaded, most of your early money went to interest, not principal. Appreciation and any extra principal you add (see the <a href="/extra-payment-mortgage-calculator/">extra payment mortgage calculator</a>) build equity faster.
- Should I choose a 20-year mortgage instead of a 30-year on a $250,000 loan?
- A 20-year is a strong middle ground - higher payment, far less interest. At 6% on $250,000, the 20-year payment is $1,791.08/mo with about $179,859 total interest, versus $1,498.88/mo and $289,595 interest over 30 years. You pay roughly $292 more monthly but save about $110,000 in interest. It splits the difference between 30-year affordability and 15-year savings.
- Is a $500,000 mortgage at 7% affordable, and what would it cost monthly?
- The P&I alone is $3,326.51 a month, and full PITI is meaningfully higher. A $500,000 loan at 7% over 30 years totals about $1,197,544, with roughly $697,544 in interest. The 28% front-end rule applies to PITI, so once you add tax, insurance, and PMI this loan typically needs gross income well above $14,000/mo to stay comfortable. Check affordability with the <a href="/loan-affordability-calculator/">loan affordability calculator</a>.
Guides & articles
- How to Calculate a Mortgage Payment, Step by Step
- 15-Year vs 30-Year Mortgage: Which Should You Choose?
- Are Mortgage Discount Points Worth It? Run the Break-Even Math First
- Conforming vs Jumbo Mortgage: The Loan Limit, the Rate, and the Down Payment
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