How to use the mortgage calculator
- Enter the loan amount, interest rate and term in years.
- Optionally fill in property tax rate, annual insurance premium, HOA fees and PMI rate.
- Read the principal and interest payment plus the total estimated housing cost.
- Review the total interest paid over the life of the loan and the payoff date.
- Scroll down to see the yearly amortization schedule showing how the balance decreases.
How the mortgage payment formula works
This mortgage calculator uses the standard annuity formula to find the fixed principal and interest (P&I) payment:
PMT = P × r / (1 - (1 + r)-n)
Where P is the loan amount, r is the monthly interest rate (annual rate divided by 12) and n is the total number of payments (years multiplied by 12).
For example, a $300,000 loan at 6.5% annual interest over 30 years has a monthly rate of 0.065 / 12 = 0.0054167 and 360 payments. The calculation gives a P&I payment of about $1,896.20. Property tax, insurance, HOA and PMI are then added on top because they do not follow this compounding formula.
What each extra cost means
A complete mortgage payment calculator accounts for more than just the bank loan. Here is what each field represents:
- Property tax: A percentage of the home value collected by local government. Enter it as an annual rate and the tool divides by 12 for the monthly share.
- Homeowners insurance: Protects against fire, theft and liability. Lenders require it. Enter the annual premium.
- HOA fee: Homeowners association dues for shared amenities like pools or landscaping. This is already a monthly figure.
- PMI: Private mortgage insurance applies when the down payment is under 20%. It protects the lender and is charged as an annual percentage of the loan.
These four items combined with P&I form the total housing expense often abbreviated as PITI (principal, interest, taxes, insurance) plus HOA.
Common mortgage terms at a glance
The table below shows the principal and interest payment per $100,000 borrowed for popular rate and term combinations. Multiply by your loan amount in hundreds to estimate your own payment.
| Rate | 15 years | 20 years | 30 years |
|---|---|---|---|
| 5.0% | $790.79 | $659.96 | $536.82 |
| 6.0% | $843.86 | $716.43 | $599.55 |
| 7.0% | $898.83 | $775.30 | $665.30 |
| 8.0% | $955.65 | $836.44 | $733.76 |
Shorter terms carry higher payments but save substantially on total interest. A 15-year loan at 6% costs roughly half the interest of a 30-year loan at the same rate.
Reading the yearly schedule
The amortization table breaks the loan into annual rows. Each row shows the total principal paid that year, the total interest paid and the remaining balance at year end. In the early years most of your payment goes toward interest. By the final years nearly all of it reduces the principal.
This mortgage interest calculator view helps you see exactly how much interest you will pay in any given year, which matters for tax deductions if you itemize. If you plan to sell or refinance before the term ends, use the mortgage refinance calculator to compare scenarios.
Edge cases and common mistakes
A few things to watch out for when using any mortgage payment calculator:
- Confusing annual and monthly rates. Always enter the annual percentage rate. The tool divides by 12 internally.
- Forgetting escrow items. Looking only at P&I understates your real obligation. Taxes and insurance can add 30% or more to the payment.
- Assuming PMI lasts forever. On conventional loans PMI usually drops off once you reach 20% equity. This tool applies it for the full term as a conservative estimate.
- Using the loan amount instead of purchase price for taxes. Property tax is based on assessed value, which may differ from your loan. Adjust the tax rate field accordingly.
For broader borrowing comparisons, the loan calculator handles non-mortgage debts, while the auto loan calculator is tailored for vehicle financing.
Worked examples
| Example | Input | Result |
|---|---|---|
| Standard 30-year fixed | Loan amount ($): 300000; Annual interest rate (%): 6.5; Loan term (years): 30; Annual property tax rate (%): 1.2; Annual homeowners insurance ($): 1500; Monthly HOA fee ($): 0; Annual PMI rate (%): 0 | Principal & interest: $1,896.20; Property tax: $300.00; Insurance: $125.00; Total monthly payment: $2,321.20; Total interest paid: $382,633.47; Total of all P&I payments: $682,633.47; Year 1: Principal $3,353.18, Interest $19,401.27, Balance $296,646.82; Year 2: Principal $3,577.74, Interest $19,176.70, Balance $293,069.08; Year 3: Principal $3,817.35, Interest $18,937.10, Balance $289,251.73; Year 4: Principal $4,073.01, Interest $18,681.44, Balance $285,178.72; Year 5: Principal $4,345.79, Interest $18,408.66, Balance $280,832.93; Year 6: Principal $4,636.83, Interest $18,117.62, Balance $276,196.10; Year 7: Principal $4,947.37, Interest $17,807.08, Balance $271,248.73; Year 8: Principal $5,278.70, Interest $17,475.75, Balance $265,970.03; Year 9: Principal $5,632.23, Interest $17,122.22, Balance $260,337.81; Year 10: Principal $6,009.43, Interest $16,745.02, Balance $254,328.38; Year 11: Principal $6,411.89, Interest $16,342.56, Balance $247,916.49; Year 12: Principal $6,841.31, Interest $15,913.14, Balance $241,075.18; Year 13: Principal $7,299.48, Interest $15,454.97, Balance $233,775.70; Year 14: Principal $7,788.34, Interest $14,966.11, Balance $225,987.36; Year 15: Principal $8,309.94, Interest $14,444.51, Balance $217,677.42; Year 16: Principal $8,866.47, Interest $13,887.98, Balance $208,810.95; Year 17: Principal $9,460.28, Interest $13,294.17, Balance $199,350.68; Year 18: Principal $10,093.85, Interest $12,660.60, Balance $189,256.83; Year 19: Principal $10,769.85, Interest $11,984.60, Balance $178,486.98; Year 20: Principal $11,491.13, Interest $11,263.32, Balance $166,995.85; Year 21: Principal $12,260.71, Interest $10,493.74, Balance $154,735.14; Year 22: Principal $13,081.83, Interest $9,672.62, Balance $141,653.30; Year 23: Principal $13,957.95, Interest $8,796.50, Balance $127,695.36; Year 24: Principal $14,892.74, Interest $7,861.71, Balance $112,802.62; Year 25: Principal $15,890.13, Interest $6,864.32, Balance $96,912.49; Year 26: Principal $16,954.32, Interest $5,800.13, Balance $79,958.16; Year 27: Principal $18,089.79, Interest $4,664.66, Balance $61,868.38; Year 28: Principal $19,301.29, Interest $3,453.16, Balance $42,567.08; Year 29: Principal $20,593.94, Interest $2,160.51, Balance $21,973.15; Year 30: Principal $21,973.15, Interest $781.30, Balance $0.00 |
| 15-year with PMI and HOA | Loan amount ($): 250000; Annual interest rate (%): 5.75; Loan term (years): 15; Annual property tax rate (%): 1; Annual homeowners insurance ($): 1200; Monthly HOA fee ($): 150; Annual PMI rate (%): 0.5 | Principal & interest: $2,076.03; Property tax: $208.33; Insurance: $100.00; HOA: $150.00; PMI: $104.17; Total monthly payment: $2,638.53; Total interest paid: $123,684.54; Total of all P&I payments: $373,684.54; Year 1: Principal $10,819.49, Interest $14,092.81, Balance $239,180.51; Year 2: Principal $11,458.27, Interest $13,454.03, Balance $227,722.24; Year 3: Principal $12,134.76, Interest $12,777.54, Balance $215,587.48; Year 4: Principal $12,851.20, Interest $12,061.11, Balance $202,736.28; Year 5: Principal $13,609.93, Interest $11,302.37, Balance $189,126.35; Year 6: Principal $14,413.46, Interest $10,498.84, Balance $174,712.89; Year 7: Principal $15,264.43, Interest $9,647.88, Balance $159,448.47; Year 8: Principal $16,165.64, Interest $8,746.67, Balance $143,282.83; Year 9: Principal $17,120.05, Interest $7,792.25, Balance $126,162.78; Year 10: Principal $18,130.82, Interest $6,781.49, Balance $108,031.96; Year 11: Principal $19,201.26, Interest $5,711.05, Balance $88,830.71; Year 12: Principal $20,334.90, Interest $4,577.41, Balance $68,495.81; Year 13: Principal $21,535.46, Interest $3,376.84, Balance $46,960.35; Year 14: Principal $22,806.92, Interest $2,105.39, Balance $24,153.43; Year 15: Principal $24,153.43, Interest $758.87, Balance $0.00 |
| Interest-only style (0.01% rate) | Loan amount ($): 400000; Annual interest rate (%): 0.01; Loan term (years): 30; Annual property tax rate (%): 0; Annual homeowners insurance ($): 0; Monthly HOA fee ($): 0; Annual PMI rate (%): 0 | Principal & interest: $1,112.78; Total monthly payment: $1,112.78; Total interest paid: $601.97; Total of all P&I payments: $400,601.97; Year 1: Principal $13,314.01, Interest $39.39, Balance $386,685.99; Year 2: Principal $13,315.34, Interest $38.06, Balance $373,370.65; Year 3: Principal $13,316.67, Interest $36.73, Balance $360,053.98; Year 4: Principal $13,318.00, Interest $35.40, Balance $346,735.97; Year 5: Principal $13,319.34, Interest $34.06, Balance $333,416.64; Year 6: Principal $13,320.67, Interest $32.73, Balance $320,095.97; Year 7: Principal $13,322.00, Interest $31.40, Balance $306,773.97; Year 8: Principal $13,323.33, Interest $30.07, Balance $293,450.64; Year 9: Principal $13,324.66, Interest $28.73, Balance $280,125.97; Year 10: Principal $13,326.00, Interest $27.40, Balance $266,799.98; Year 11: Principal $13,327.33, Interest $26.07, Balance $253,472.65; Year 12: Principal $13,328.66, Interest $24.74, Balance $240,143.98; Year 13: Principal $13,330.00, Interest $23.40, Balance $226,813.99; Year 14: Principal $13,331.33, Interest $22.07, Balance $213,482.66; Year 15: Principal $13,332.66, Interest $20.74, Balance $200,150.00; Year 16: Principal $13,334.00, Interest $19.40, Balance $186,816.00; Year 17: Principal $13,335.33, Interest $18.07, Balance $173,480.68; Year 18: Principal $13,336.66, Interest $16.74, Balance $160,144.01; Year 19: Principal $13,338.00, Interest $15.40, Balance $146,806.02; Year 20: Principal $13,339.33, Interest $14.07, Balance $133,466.69; Year 21: Principal $13,340.66, Interest $12.74, Balance $120,126.02; Year 22: Principal $13,342.00, Interest $11.40, Balance $106,784.03; Year 23: Principal $13,343.33, Interest $10.07, Balance $93,440.69; Year 24: Principal $13,344.67, Interest $8.73, Balance $80,096.03; Year 25: Principal $13,346.00, Interest $7.40, Balance $66,750.03; Year 26: Principal $13,347.34, Interest $6.06, Balance $53,402.69; Year 27: Principal $13,348.67, Interest $4.73, Balance $40,054.02; Year 28: Principal $13,350.01, Interest $3.39, Balance $26,704.02; Year 29: Principal $13,351.34, Interest $2.06, Balance $13,352.68; Year 30: Principal $13,352.68, Interest $0.72, Balance $0.00 |
FAQ
How is the principal and interest payment calculated?
The formula is PMT = P * r / (1 - (1 + r)^-n), where P is the loan amount, r is the monthly interest rate and n is the total number of monthly payments. This produces a fixed payment that fully pays off the loan by the end of the term.
Does this mortgage calculator include property taxes and insurance?
Yes. You can enter an annual property tax rate, an annual insurance premium, a monthly HOA fee and an annual PMI rate. These are added to the principal and interest to show the total estimated housing cost.
What is PMI and when do I need it?
Private mortgage insurance protects the lender when your down payment is less than 20% of the home price. It is typically charged as an annual percentage of the loan amount and added to your payment until you build enough equity.
Can I use this tool to compare a 15-year and 30-year mortgage?
Yes. Change the term field to 15 or 30 and observe how the payment and total interest change. Shorter terms have higher payments but significantly lower total interest costs.
Is my data sent to a server?
No. All calculations happen locally in your browser. Nothing you type is transmitted or stored.
Why does the total interest seem so high?
Over a 30-year term at current rates, total interest often exceeds the original loan amount. This is the cost of spreading repayment over decades. Extra principal payments reduce total interest substantially.