30-Year Mortgage Calculator

What is a 30-year mortgage?

The 30-year fixed-rate mortgage is the standard American home loan. You borrow a lump sum, repay it over 360 monthly payments (30 years), and your interest rate stays the same for the entire loan. The long term makes monthly payments low enough that most home buyers can qualify, but it means you'll pay significantly more in total interest than shorter-term loans. On a $400,000 loan at 6.5%, a 30-year mortgage totals over $510,000 in interest over the life of the loan — vs roughly $227,000 on a 15-year at the same rate.

Fixed means the rate you close at is the rate you keep until payment 360 — there is no adjustment date to watch, no cap to monitor, and no balloon payment at the end. The loan fully amortizes: each scheduled payment covers that month's interest and reduces the balance, and the final payment retires the last dollar. Because interest is charged on the remaining balance, the split shifts slowly rather than suddenly. On the $400,000 example worked out below, payment 1 is $2,166.67 of interest and $361.61 of principal; by payment 180 the split is $1,572.11 of interest and $956.16 of principal.

Most buyers choose the 30-year for one reason: it produces the lowest qualifying payment, which matters because a lender measures your debt-to-income ratio against that number. The cost of the choice is interest — $510,178 on a $400,000 loan at 6.5%. Whether that trade-off fits you depends on how long you will keep the loan and what else your money needs to do; the 15-year vs 30-year comparison walks through that decision. If you are still sizing the purchase itself, the affordability calculator starts from income instead of from a payment.

How to use this calculator

1. Enter your home loan amount (purchase price minus down payment).
2. Enter your interest rate — current 30-year rates are listed on our rates page.
3. Confirm the term is set to 30 years (360 months).
4. Optionally add property taxes, homeowners insurance, HOA fees, and PMI for a full PITI estimate.
5. Click Calculate to see monthly payment, total interest, total cost, and a full amortization schedule.

A realistic set of inputs for a $500,000 home with 20% down: loan amount $400,000, rate whatever our rates page shows that day (the worked examples on this page use 6.5%), term 360 months. For the optional PITI fields, budget property tax at roughly 0.9% to 1.2% of value a year — $375 to $500 a month on $500,000 — and homeowners insurance at $1,200 to $2,000 a year, which is $100 to $167 a month. Add HOA dues only if the property has them. If your down payment is under 20%, estimate the mortgage insurance line with our PMI calculator; premiums commonly run 0.5% to 1.5% of the loan amount a year, or about $167 to $500 a month on $400,000.

Understanding your results

This calculator shows your monthly principal & interest payment, then optionally your full PITI payment (Principal, Interest, Taxes, Insurance). The total interest paid column shows you the real cost of the loan — the difference between what you borrowed and what you'll repay. The amortization schedule breaks down how each payment is split between principal and interest. Early in the loan, most of your payment goes to interest; by year 20+, you're paying mostly principal.

The percentages are worth checking yourself. In the $400,000 example, 85.7% of payment 1 is interest; at payment 180 it is 62.2%; at payment 300 it is 27.7%; and the final payment is 0.5% interest. Total interest is simply what you pay the lender on top of the $400,000 you borrowed — the gap between the $910,178 you repay and the $400,000 you received. For the mechanics behind those numbers — rate per period, compounding, and how extra principal shortens the schedule — read the amortization guide.

Tips to save on a 30-year mortgage

The 30-year loan gives you flexibility. Three strategies to consider: (1) make extra principal payments when you can — even $100/month extra saves thousands in interest and shaves years off the loan; (2) refinance to a shorter term if rates drop and you've built equity; (3) recast the loan (re-amortize) after a large principal payment to lower the monthly payment without refinancing.

Extra payments are the highest-return move available to you, because every dollar goes to principal and every dollar of principal stops earning 6.5% interest for the rest of the loan. Adding $200 a month to the $400,000 example pays it off in 24 years 5 months instead of 30 and cuts total interest from $510,178 to $398,286 — a saving of $111,892. If you would rather automate it, a biweekly schedule sends half a payment every two weeks, which adds up to one extra payment a year and produces savings in the same range; model both approaches in the biweekly calculator, and see the extra payments guide for lump sums and recasting.

The table below restates the same loan with a standing extra-payment instruction, regular payment unchanged at $2,528.27, extra applied to principal the same month it is made:

Notice that $500 a month retires the loan 10 years 7 months early and saves more than $205,000 of interest — the argument for treating extra principal as a standing monthly instruction rather than an occasional lump sum.

How your 30-year payment is calculated

Your lender divides the annual interest rate by 12 to get a monthly rate, then answers one question: what level payment, made 360 times, exactly exhausts the balance? The answer is the standard amortization formula, which weights each payment by the compounding factor of the loan.

M = P × [ i (1 + i)ⁿ ] ÷ [ (1 + i)ⁿ − 1 ]

Here M is the monthly principal and interest payment, P is the loan amount, i is the monthly interest rate (annual rate ÷ 12), and n is the number of payments (360 on a 30-year loan).

Worked example: $400,000 at 6.5% for 30 years

Step 1: the monthly rate is 6.5% ÷ 12 = 0.005416667. Step 2: n = 30 × 12 = 360 payments. Step 3: the compounding factor is (1 + 0.005416667)³⁶⁰ = 6.991798. Step 4: multiply and divide — 400,000 × 0.005416667 × 6.991798 = 15,148.90, and 6.991798 − 1 = 5.991798, so M = 15,148.90 ÷ 5.991798 = $2,528.27. Step 5: total repayment is $2,528.27 × 360 = $910,178, which makes lifetime interest $910,178 − $400,000 = $510,178.

Step 6 compares the first year with the last. During year 1 you send $30,339 to the lender — $25,868 of it is interest and only $4,471 reduces the balance, leaving $395,529 owed after month 12. During the final year, just $1,042 of the payments is interest, so $29,298 goes to principal and the balance reaches zero. The interest is front-loaded: $345,326 of the $510,178 is paid in the first 15 years and $164,852 across the last 15. Your first payment is $2,166.67 of interest; your 360th is $13.62.

Worked scenarios: rate and down payment

Three inputs move your payment — the rate, the amount borrowed, and the term. These tables hold two of them constant so you can see the effect of one change at a time. All figures are principal and interest only; taxes, insurance, and PMI are separate lines.

Rate scenarios: $400,000 loan, 30-year term

Each half-percent of rate is worth about $130 a month and roughly $47,000 across 360 payments. Moving from 6.50% to 7.00% costs $132.94 a month and $47,858 of lifetime interest — which is why same-day rate shopping is one of the highest-value hours you can spend on this purchase.

Down payment scenarios: $500,000 home, 6.50%, 30-year term

Coming to the table with 20% down instead of 5% cuts the payment by $474.05 a month and lifetime interest by $95,658 — and it removes PMI, which on the $475,000 loan would add roughly $200 to $600 a month. Cash versus payment is a personal trade: the down payment calculator runs it for your price point, and the PMI calculator sizes the insurance line you would avoid.

How taxes, insurance, and PMI change the payment

Principal and interest are only the loan. The payment that actually leaves your account every month adds three more lines, and two of them depend on things outside the loan: your local tax assessment and your insurance premium. Take a $500,000 purchase with 5% down, which means a $475,000 loan, and a straightforward budget — property tax at 1.0% of value a year is $416.67 a month, homeowners insurance at $1,500 a year is $125 a month, and PMI at 0.7% of the loan amount a year is $277.08 a month.

The full PITI payment is $3,002.32 + $416.67 + $125 + $277.08 = $3,821.07 — about $819 more than the $3,002.32 principal-and-interest figure the calculator shows first. Raise the down payment to 20% ($100,000 cash) and the loan drops to $400,000, PMI disappears entirely, and the same house costs $2,528.27 + $416.67 + $125 = $3,069.94 a month.

Lenders qualify you on the full number, not the loan payment. At the common 28% front-end guideline, the 5%-down version needs about $13,647 of gross monthly income while the 20%-down version needs about $10,964 — a $2,683 monthly income difference created by insurance and PMI alone. Price your county's tax rate with the property tax calculator before you fall for a price point that only works before escrow.

30-year vs 15-year vs 20-year: total cost compared

Same loan, same rate, three terms. The only variable is how fast you repay.

The 20-year is the middle path: $454.02 more a month retires $194,428 of interest and finishes five years sooner. The 15-year costs $956.16 more a month than the 30-year and saves $282,981 in interest. Lenders also usually price the 15-year 0.50% to 0.75% below the 30-year, so at 5.90% the same $400,000 15-year payment falls to $3,353.86 with lifetime interest of $203,694 — $306,484 less than the 30-year at 6.50%. Run your own numbers in the 15-year calculator and the 20-year calculator, then weigh the decision factors in the 15-year vs 30-year guide. The savings column is arithmetic, not a promotion: a shorter term keeps the balance outstanding for fewer months, so every dollar of interest accrues for less time. What you are actually shopping for is the higher monthly commitment you can afford to hand over every month for years — and only your own budget can answer that.

30-year mortgage strategy for 2026

Four decisions do more than everything else combined.

1. Shop quotes inside a two-week window. Get estimates from three to five lenders within about 14 days so the credit inquiries are scored as one, and take the quotes on the same day: rate sheets change between visits, and comparing Tuesday's quote against last month's flyer hides the difference.
2. Settle points versus no points with arithmetic. One point costs 1% of the loan — $4,000 on $400,000 — and typically buys about 0.25% of rate, worth $65.40 a month. Break-even is 61 months. If you expect to keep the loan past year five, points pay for themselves; if you may sell or refinance sooner, keep the cash. Model your own hold period in the mortgage points calculator.
3. Qualify on ratios, not enthusiasm. Hold total housing under 28% of gross monthly income and total debt under 36% as your own targets, even though many lenders will approve 43% or more. On $12,000 of gross monthly income that is $3,360 for housing — a $2,528 payment plus taxes and insurance fits; on $8,000 it does not. Check your numbers in the debt-to-income calculator.
4. Do not plan around a future refinance. Closing costs run 2% to 5% of the loan amount, or $8,000 to $20,000 on $400,000, so the payment you sign in 2026 has to be one you can carry for years without depending on rates falling. Buy the payment first and treat any later refinance as a bonus; the refinance calculator shows what a rate drop would actually be worth.
5. Build a payment reserve before you optimize anything. Six months of the full payment — $15,170 on this example — is the difference between a plan that survives a job gap and one that forces a sale. Fund the reserve first, then attack principal: the interest saving is real, but it cannot pay the mortgage in a bad month.

Common mistakes on a 30-year mortgage

• Comparing quotes that are not like-for-like. Different points, different lock periods, and quotes taken weeks apart make a false winner. One point is $4,000 on a $400,000 loan and moves the rate about 0.25%; a stale quote can be half a point off the market. Request the same loan amount, same points, and same lock window from every lender on the same day.
• Budgeting principal and interest but spending principal, taxes, and insurance. The payment on this page is $2,528.27, yet taxes and insurance commonly add $500 to $700 a month. Qualify on the smaller number and your real budget breaks in month one.
• Judging the loan by lifetime interest alone. "$510,178 of interest" is accurate and it is not a reason to choose a $956-higher payment you cannot hold through a job change. Total cost and monthly risk are separate questions.
• Skipping the rate-lock conversation. Locks typically run 30 to 60 days; if closing slips, extensions cost money. Ask about lock length, cost, and float-down policy before you apply, not after you are in underwriting.
• Making extra payments while carrying more expensive debt. An extra $200 a month saves $111,892 here, but if your credit card charges more than 6.5% — most do — the card is the better place for that dollar. Pay the expensive debt first, then redirect it to principal.
• Ignoring escrow growth. Property taxes and insurance premiums rise, so a payment that fits at closing can be $100 a month higher in three years. Ask for the current escrow analysis and stress-test your budget at the higher figure.
• Treating the pre-qualification number as your budget. Pre-qualifications often run at the maximum allowed ratios — 43% to 45% back-end — not the 28% and 36% you should hold yourself to. On $12,000 of gross monthly income, a 43% cap allows $5,160 of total monthly debt while a 36% target allows $4,320. Borrowing at the maximum leaves no margin; keeping that $840 a month unspent does.
• Opening new credit right after closing. A $400-a-month furniture or car payment added in the first year is 3.3 percentage points of debt-to-income on a $12,000 income, and it can cost you refinance eligibility later.

Frequently asked questions

Should I pay points to lower my rate? Each point (1% of the loan amount) typically lowers your rate by about 0.25%. Buying points makes sense if you plan to stay in the home long enough to recoup the upfront cost from monthly savings — usually 3–5 years minimum.

What if I pay extra each month? Extra payments go directly to principal, which reduces your balance faster and saves substantial interest. Use our extra payment calculator to see the impact.

Can I switch to a 15-year loan later? Yes, through a refinance. Many homeowners wait until rates drop or until they've built 20–25% equity, then refinance into a 15-year to keep the payment manageable while paying off faster.

How much interest will I really pay on a $400,000 loan at 6.5%? $510,178 over 360 payments — your $2,528.27 payment adds up to $910,178, so interest is 56% of every dollar you repay. Year 1 alone costs $25,868 in interest while only $4,471 of principal is repaid.

Should I buy points or make a bigger down payment? One point costs 1% of the loan and typically saves about 0.25% of rate. On $400,000 that is $4,000 upfront for $65.40 a month, with break-even at 61 months. The same $4,000 as extra down payment lowers the loan to $396,000, cuts the payment by $25.28, and saves $5,102 of interest over the term. Points win if you stay past break-even; extra down payment wins if it pushes you to 20% and removes PMI.

Why is my first payment almost all interest? Interest accrues on the outstanding balance, which is highest on day one: $400,000 × 6.5% ÷ 12 = $2,166.67 of your first $2,528.27 payment, leaving $361.61 for principal. By payment 300 the interest charge has fallen to $699.92 and $1,828.35 goes to principal.

Does a 30-year mortgage require PMI? Only when you put down less than 20%. On a $500,000 home with 5% down you borrow $475,000, and PMI commonly runs 0.5% to 1.5% of the loan amount a year — about $200 to $600 a month. You can request removal once you reach 80% of the original value, and your servicer must cancel it automatically at 78%.

Should I lock my interest rate? Locks typically run 30 to 60 days and protect the quoted rate while the loan closes. Confirm the lock period, the cost of an extension, and the policy if closing slips — before you apply.

Related calculators

• 15-Year Mortgage Calculator
• Full Mortgage Calculator
• Affordability Calculator
• 15-Year vs 30-Year Mortgage
• 20-Year Mortgage Calculator
• Amortization Guide