Mortgage Calculator
Calculate monthly payment, total interest, and a quick amortization preview.
| # | Date | Payment | Principal | Interest | Balance |
|---|---|---|---|---|---|
| Run a calculation to see the schedule. | |||||
Important Note : a full mortgage payment may include principal, interest, taxes, insurance, mortgage insurance, and possibly other costs. CFPB defines PITI as principal, interest, taxes, and insurance, and separately notes that PMI may be required for a conventional loan when the down payment is less than 20%.
Use this Mortgage Calculator to estimate your monthly mortgage payment, total interest, payoff date, and amortization schedule. Enter the home price, down payment, interest rate, loan term, and optional taxes, insurance, PMI, and extra monthly payment to estimate the cost of a home loan.
This calculator is useful for comparing mortgage scenarios, estimating principal and interest, planning a home-buying budget, and seeing how extra payments may reduce interest and shorten the loan term.
Reviewed by: Ajax Calculator Team
Last updated: April 30, 2026
Method source: Standard fixed-rate mortgage amortization formulas using loan amount, monthly interest rate, loan term, scheduled payment, optional extra principal payment, and monthly estimates for property tax, home insurance, and PMI.
Editorial standards: See our Editorial Policy for how we review and update calculator content.
What This Mortgage Calculator Does
This mortgage calculator estimates the main costs of a fixed-rate home loan. It can calculate:
- Loan amount after down payment
- Monthly principal and interest payment
- Total monthly payment including property tax, home insurance, and PMI
- Total interest over the loan term
- Total amount paid over time
- Estimated payoff date
- Amortization preview for the first payments
- Effect of an optional extra monthly principal payment
The calculator is designed for quick mortgage planning. It gives an estimate, not a final lender quote or official loan disclosure.
Mortgage Payment Formula
For a standard fixed-rate mortgage, the monthly principal and interest payment is calculated with this formula:
M = P × [r(1 + r)n] ÷ [(1 + r)n − 1]
Where:
- M = monthly principal and interest payment
- P = loan principal or loan amount
- r = monthly interest rate, calculated as annual rate ÷ 12
- n = total number of monthly payments
The loan amount is usually calculated as:
Loan amount = Home price − Down payment
If you enter a loan amount manually, the calculator uses that value instead of calculating it from home price and down payment.
Total Monthly Mortgage Payment Formula
The calculator separates the base mortgage payment from the broader estimated monthly housing payment.
Monthly principal and interest = scheduled loan payment
Monthly property tax = annual property tax ÷ 12
Monthly home insurance = annual home insurance ÷ 12
Total monthly estimate = principal and interest + monthly tax + monthly insurance + monthly PMI
This broader monthly estimate is closer to a PITI-style payment, but it may still exclude costs such as HOA dues, flood insurance, condo fees, maintenance, utilities, closing costs, and lender fees.
What Is PITI?
PITI stands for principal, interest, taxes, and insurance. These are the four common parts of a monthly mortgage-related housing payment.
- Principal reduces the loan balance.
- Interest is the cost of borrowing money.
- Taxes are property taxes assessed by local governments.
- Insurance usually refers to homeowners insurance.
Some borrowers also pay mortgage insurance, such as PMI, when the down payment is small or the loan type requires it.
Worked Example
Suppose you are buying a home with these assumptions:
| Input | Example Value |
|---|---|
| Home price | $350,000 |
| Down payment | $20,000 |
| Loan amount | $330,000 |
| Interest rate | 6.5% |
| Loan term | 30 years |
| Annual property tax | $3,600 |
| Annual home insurance | $1,200 |
| Monthly PMI | $75 |
The estimated monthly principal and interest payment is about:
$2,085.82
The monthly property tax estimate is:
$3,600 ÷ 12 = $300
The monthly home insurance estimate is:
$1,200 ÷ 12 = $100
Adding PMI gives an estimated total monthly payment of:
$2,085.82 + $300 + $100 + $75 = $2,560.82
In this example, the total monthly estimate is higher than the principal-and-interest payment because property tax, insurance, and PMI are added separately.
How to Use the Mortgage Calculator
- Enter the home price.
- Enter the down payment as a dollar amount or percentage.
- Use the loan amount override only if you already know the exact loan amount.
- Enter the annual interest rate.
- Enter the loan term in years, such as 15 or 30 years.
- Choose a start date to estimate the payoff date and schedule labels.
- Optionally enter an extra monthly payment if you plan to pay extra toward principal.
- Optionally enter annual property tax, annual home insurance, and monthly PMI.
- Click Calculate to see your estimated payment, total interest, payoff date, and amortization preview.
How to Interpret the Results
Monthly payment (P&I) shows the estimated principal and interest payment for the loan itself.
Total monthly including tax, insurance, and PMI adds the estimated monthly property tax, homeowners insurance, and PMI amounts to the loan payment.
Total interest shows the estimated interest paid over the life of the loan, based on the selected loan term and interest rate.
Total paid estimates the overall amount paid based on the calculator’s payment assumptions.
Payoff date estimates when the loan may be paid off if payments follow the entered schedule.
Amortization preview shows how early payments are split between principal and interest and how the remaining balance changes over time.
What Is Amortization?
Amortization is the process of paying down a loan through scheduled payments. In a fixed-rate mortgage, the monthly principal and interest payment usually stays the same, but the split changes over time.
Early in the loan, a larger share of the payment goes toward interest. Later in the loan, more of each payment goes toward principal. This happens because interest is calculated on the remaining balance, and the balance gradually falls as principal is repaid.
How Extra Monthly Payments Affect a Mortgage
An extra monthly payment can reduce the loan balance faster. When extra money is applied to principal, the future interest is calculated on a smaller balance. This can reduce total interest and may shorten the payoff time.
For example, adding $100 per month to a mortgage payment can make a meaningful difference over many years. The exact savings depend on the loan amount, interest rate, term, and when the extra payments start.
Before making extra payments, check whether your loan has prepayment penalties and confirm that the lender applies the extra amount to principal.
Down Payment: Dollar Amount vs Percentage
The calculator allows down payment as either a dollar amount or a percentage of the home price.
Dollar down payment:
Loan amount = home price − down payment amount
Percentage down payment:
Down payment amount = home price × down payment percentage
For example, a 20% down payment on a $350,000 home is:
$350,000 × 20% = $70,000
The estimated loan amount would be:
$350,000 − $70,000 = $280,000
What Is PMI?
PMI stands for private mortgage insurance. It is often required on conventional loans when the borrower makes a down payment of less than 20% of the home’s purchase price.
PMI protects the lender if the borrower stops making payments. It does not protect the borrower from foreclosure, missed-payment consequences, or loss of the home. If PMI applies, enter the monthly amount in the PMI field to include it in the total monthly estimate.
Interest Rate vs APR
A mortgage interest rate is the rate used to calculate interest on the loan balance. APR, or annual percentage rate, can include the interest rate plus certain loan costs and fees.
For monthly payment estimates, mortgage calculators commonly use the interest rate, not a full fee-inclusive APR. If your lender quotes both an interest rate and APR, use the rate that matches what you are trying to estimate. For a basic monthly principal-and-interest payment, the note rate or interest rate is usually the more direct input.
15-Year vs 30-Year Mortgage
The loan term has a major effect on both monthly payment and total interest.
| Loan Term | Typical Effect | Tradeoff |
|---|---|---|
| 15 years | Higher monthly payment | Usually less total interest and faster payoff |
| 30 years | Lower monthly payment | Usually more total interest over time |
A shorter loan term can save interest but may make the monthly payment harder to afford. A longer term can lower the monthly payment but usually increases total interest.
Mortgage Payment Example Table
| Loan Amount | Rate | Term | Estimated P&I Payment |
|---|---|---|---|
| $250,000 | 6.5% | 30 years | $1,580.17 |
| $300,000 | 6.5% | 30 years | $1,896.20 |
| $350,000 | 6.5% | 30 years | $2,212.24 |
| $300,000 | 6.5% | 15 years | $2,613.32 |
These examples show principal and interest only. Taxes, insurance, PMI, HOA fees, and other housing costs are not included in this table.
Common Uses for a Mortgage Calculator
This calculator can help you:
- Estimate monthly mortgage payment before buying a home
- Compare different home prices and down payments
- Estimate principal and interest for 15-year and 30-year loans
- Add property tax, insurance, and PMI to estimate a broader monthly cost
- See how much interest may be paid over the loan term
- Estimate how extra monthly payments affect payoff time
- Compare mortgage scenarios before speaking with a lender
Costs This Calculator May Not Include
The calculator includes optional property tax, home insurance, and PMI, but a real homeownership budget can include more costs.
- HOA or condo fees
- Flood insurance
- Mortgage points
- Origination fees
- Closing costs
- Appraisal and inspection fees
- Title insurance
- Maintenance and repairs
- Utilities
- Moving costs
For a more complete budget, combine this calculator with a closing cost estimate and a monthly homeownership cost estimate.
Assumptions and Limitations
- The calculator assumes a fixed interest rate.
- It assumes regular monthly payments.
- It uses the entered loan term to calculate total monthly payments.
- It estimates property tax as annual property tax divided by 12.
- It estimates home insurance as annual insurance divided by 12.
- It treats PMI as a fixed monthly amount entered by the user.
- It does not model adjustable-rate mortgage changes.
- It does not include closing costs, lender fees, points, HOA dues, or maintenance.
- It does not calculate escrow changes over time.
- It does not guarantee loan approval, lender pricing, or final payment amount.
Tips for More Accurate Mortgage Estimates
- Use the actual loan amount if you already have a lender estimate.
- Use a realistic property tax estimate for the home’s location.
- Get a homeowners insurance quote instead of guessing.
- Include PMI if your lender says it will apply.
- Compare both 15-year and 30-year terms.
- Test several interest rates to see how sensitive the payment is.
- Remember that the lender’s final payment may differ from this estimate.
Related Calculators
- Mortgage Interest Calculator
- Mortgage Calculator with Taxes and Insurance
- Mortgage/Loan Amortization Calculator
- Refinance Calculator
- Loan Calculator
- Interest Rate Calculator
References
- Consumer Financial Protection Bureau: What Is PITI?
- Consumer Financial Protection Bureau: Principal and Interest Payment vs Total Monthly Payment
- Consumer Financial Protection Bureau: Private Mortgage Insurance
- Consumer Financial Protection Bureau: Mortgage Interest Rate vs APR
- Consumer Financial Protection Bureau: Loan Estimate Explainer
Frequently Asked Questions
What does a mortgage calculator do?
A mortgage calculator estimates the monthly payment, total interest, total paid, payoff date, and amortization schedule for a home loan based on the loan amount, interest rate, and loan term.
How is a monthly mortgage payment calculated?
A fixed-rate mortgage payment is calculated using the loan amount, monthly interest rate, and total number of payments. The formula spreads principal and interest across the full loan term.
What is included in a mortgage payment?
A basic mortgage payment includes principal and interest. A broader monthly housing payment may also include property taxes, homeowners insurance, PMI, HOA dues, and other costs.
What is the difference between principal and interest?
Principal is the part of the payment that reduces your loan balance. Interest is the cost of borrowing money from the lender.
Does this calculator include taxes and insurance?
Yes, it includes optional annual property tax and annual homeowners insurance fields. The calculator divides each annual amount by 12 and adds it to the monthly estimate.
Does this calculator include PMI?
Yes, it includes an optional monthly PMI field. If you do not have PMI, leave that field blank or enter zero.
What is PMI?
PMI stands for private mortgage insurance. It is often required on conventional loans when the down payment is less than 20% of the purchase price.
Why is my lender’s payment different from this estimate?
Your lender’s payment may differ because of exact loan terms, APR rules, escrow setup, mortgage insurance, taxes, insurance premiums, closing costs, fees, points, and rounding.
Does making extra mortgage payments save interest?
Extra payments can save interest if they are applied to principal. Reducing principal earlier lowers the balance used to calculate future interest.
Can I use this calculator for an adjustable-rate mortgage?
This calculator is mainly designed for fixed-rate mortgage estimates. Adjustable-rate mortgages can change over time, so the actual future payment may differ.
Disclaimer
This calculator is for educational and planning purposes only. It does not provide financial, mortgage, legal, tax, or lending advice. Actual mortgage payments, loan terms, APR, taxes, insurance, PMI, escrow amounts, closing costs, fees, and approval requirements may vary by lender, location, borrower profile, loan program, and market conditions. Always review official loan estimates, closing disclosures, and lender terms before making a home financing decision.