Mortgage Calculator

This mortgage calculator helps you estimate your monthly payment, total interest, and payoff date. To make the estimate more realistic, you can include property taxes, homeowners insurance, and extra payments.

Use it to answer common questions like: “Can I afford this payment?”, “How much interest will I pay over the life of the loan?”, “Does paying an extra $200/month actually matter?”

Calculate your mortgage payment

Tip: For a “true monthly housing cost”, include taxes + insurance (often called PITI).

Add one-time or recurring extra payments to reduce interest and loan term.

Quick start (2 minutes)

  1. Enter Home price and Down payment. The loan amount is usually: price − down payment.
  2. Choose a loan term (commonly 15 or 30 years) and an expected interest rate.
  3. Add taxes and insurance if you want a realistic monthly budget.
  4. Add an extra payment to see how it changes total interest and payoff date.
  5. Compare scenarios (rate changes, different down payment, different term).

What is included in a mortgage payment (PITI)

Many borrowers focus on principal + interest, but lenders and homeowners often talk about PITI: Principal, Interest, Taxes, and Insurance. If your lender collects taxes/insurance monthly and pays them later, that’s typically done through an escrow account. Escrow amounts can change if taxes or premiums change.

Principal

The part of your payment that reduces your loan balance.

Interest

The cost of borrowing. It’s typically higher early in the loan because the balance is largest.

Property taxes

Local taxes that may change over time. Including them avoids underestimating your monthly budget.

Homeowners insurance

Insurance that helps protect the property. Premiums depend on location and coverage.

Reference (educational): CFPB – What is PITI?

PMI and APR (important when comparing offers)

PMI (Private Mortgage Insurance) may apply to some conventional loans when the down payment is below a commonly referenced threshold (often 20%). PMI typically increases the monthly cost and protects the lender. If you expect PMI, treat it like an extra monthly housing cost and include it in your budget.

CFPB – What is PMI?

Interest rate vs APR: the interest rate reflects the borrowing cost on the principal. APR is a broader annualized measure that can include certain fees in addition to interest. If you’re comparing offers, APR can help you compare the total borrowing cost more fairly.

CFPB – Difference between interest rate and APR

How to compare mortgage offers (without guessing)

When you compare lenders, the lowest advertised rate does not always mean the lowest total cost. Mortgage pricing can include fees, discount points, and different closing cost structures. Two offers can produce similar monthly payments but very different cash needed at closing and long-term cost.

A simple comparison method

  1. Use the same home price, down payment, and loan term for every offer you test.
  2. Compare APR (when available) alongside the interest rate to get a broader view of cost that may include certain charges.
  3. Compare cash needed at closing (down payment + closing costs + prepaids), not only the monthly payment.
  4. Stress-test affordability by modeling a slightly higher rate (e.g., +0.5% to +1.0%) and check if the payment still fits your budget.

Interest rate

The borrowing cost applied to the loan balance. It strongly affects the monthly principal + interest payment.

APR

A broader annualized measure of borrowing cost that can include certain fees in addition to interest. It can be useful for comparing offers with different fee structures.

Tip: If two offers have similar payments, the deciding factor is often the fee structure and cash needed at closing—not the headline rate.

The math behind the payment (amortization, explained)

Most fixed-rate mortgages are amortizing loans. That means you usually pay the same principal+interest amount each month, but the split changes. Interest is calculated on the remaining balance, so early payments are interest-heavy. Over time, more of each payment goes toward principal.

Payment formula (principal + interest)

A standard fixed-rate mortgage monthly payment (principal + interest) is commonly modeled using the amortization formula:

M = P × [ r(1+r)^n ] / [ (1+r)^n − 1 ]
  • M = monthly principal+interest payment
  • P = loan principal (amount borrowed)
  • r = monthly interest rate (annual rate ÷ 12)
  • n = total number of payments (years × 12)

Educational reference: Mortgage calculator (amortization formula)

Worked example (step-by-step)

Example: loan amount $280,000, term 30 years, rate 6.00%.

  • Annual rate = 0.06 → monthly rate r = 0.06 / 12 = 0.005
  • Total payments n = 30 × 12 = 360
  • Plug into the formula to estimate the monthly principal+interest payment

Your full monthly housing cost may also include taxes, insurance, and possibly PMI — that’s why adding them in the calculator is useful.

Scenario comparisons (how small changes affect cost)

Looking at a single estimate is useful, but comparing scenarios often reveals where the biggest cost differences come from. Below are common side-by-side comparisons you can model using this calculator.

15-year vs 30-year term

Shorter terms usually have higher monthly payments but significantly lower total interest over the life of the loan. Longer terms improve cash flow but increase total borrowing cost.

  • 15-year: higher payment, lower total interest
  • 30-year: lower payment, higher total interest

With vs without extra payments

Adding even modest recurring extra payments can reduce interest and shorten the payoff period, especially early in the loan.

  • Baseline payment only
  • Baseline + fixed monthly extra payment

10% vs 20% down payment

A larger down payment reduces the loan amount and can lower the monthly payment. It may also affect whether PMI applies.

  • Lower down payment: higher loan, possible PMI
  • Higher down payment: lower loan, no PMI

Tip: Change only one variable at a time (term, rate, down payment, or extra payment) to clearly see how each factor affects the result.

Don’t forget “cash needed at closing”

Your monthly payment is only one part of affordability. Many buyers also need to plan for upfront cash, such as the down payment plus closing costs and prepaid items. These can vary significantly by lender and location.

  • Down payment: the cash you put toward the purchase price.
  • Closing costs: fees related to processing the loan and the purchase (varies by lender/location).
  • Prepaids: items like prepaid interest, escrow deposits, or insurance premiums (depending on the loan).

Educational reference: CFPB – Closing Disclosure overview

Simple affordability checks (not advice)

A calculator can estimate payments, but affordability depends on your full budget. Here are neutral “checks” you can use when reviewing your result (these are not rules and not financial advice):

Stress-test the interest rate

Try increasing the rate by 0.5–1.0% and see if the payment still fits your budget.

Compare full monthly cost

Compare principal+interest vs PITI. Many “surprises” come from taxes/insurance not being included.

The 28/36 guideline (a budgeting reference, not a rule)

Some budgeting frameworks use the “28/36” guideline to sanity-check affordability. It’s not an approval rule and it won’t apply to every household, but it can help you interpret your calculator result in the context of your overall budget.

28% housing ratio

A commonly referenced benchmark is keeping total monthly housing costs around 28% of gross monthly income. For mortgages, housing costs often include PITI (principal, interest, taxes, insurance).

Housing Ratio = (Monthly Housing Cost ÷ Gross Monthly Income) × 100

36% total debt ratio

Another commonly referenced benchmark is keeping total monthly debt payments around 36% of gross monthly income. This includes housing costs plus other debts like car loans, student loans, and credit card minimum payments.

Total Debt Ratio = (All Monthly Debt ÷ Gross Monthly Income) × 100

How to use this with your calculator result

  • If your estimated PITI is close to (or above) your comfort level, try modeling a higher down payment, a smaller loan amount, or a higher rate stress-test.
  • If you have other monthly debts, compare your full debt load (housing + other debts) against your income for a more realistic view.
  • Use the guideline as a budgeting reference only—actual lender requirements and your personal situation may differ.

Note: This is an educational budgeting guideline, not a lending standard or financial advice. Always verify affordability based on your full budget and lender terms.

LTV and DTI basics (affordability signals, not rules)

Lenders often look at a few common ratios to understand risk and affordability. These ratios are not universal “approval rules”, but they’re useful for setting realistic expectations when reviewing your mortgage estimate.

Loan-to-Value (LTV)

LTV compares the loan amount to the home value (or purchase price). A higher LTV usually means less equity upfront and can affect pricing, approval requirements, or whether mortgage insurance is needed.

LTV = (Loan Amount ÷ Home Value) × 100

Example: If you borrow $280,000 on a $350,000 home, LTV ≈ 80%.

Debt-to-Income (DTI)

DTI compares your monthly debt payments to your gross monthly income. It’s commonly used to evaluate whether a payment fits within your overall budget alongside other obligations.

DTI = (Total Monthly Debt ÷ Gross Monthly Income) × 100

Tip: Include housing costs (PITI) plus other debts like auto loans, student loans, and credit cards for a more realistic estimate.

How to use these ratios with your calculator result

  • If your estimate feels tight, try increasing the down payment (lower LTV) or testing a lower rate / smaller loan amount.
  • If you’re unsure about affordability, compare the full monthly cost (PITI) against your budget and other monthly debts (DTI-style thinking).
  • Always verify lender-specific requirements and definitions—different programs can calculate ratios differently.

Note: This section is educational and does not determine approval or pricing. Final underwriting rules depend on the lender and loan program.

Common mistakes

  • Ignoring taxes and insurance and budgeting only for principal+interest.
  • Comparing only the interest rate instead of reviewing APR and fee structure.
  • Not modeling extra payments consistently (occasional extra payments may have smaller impact).
  • Forgetting variable costs can change (taxes/insurance can rise over time).

PMI removal and equity milestones

Private Mortgage Insurance (PMI) is not always permanent. As you pay down your mortgage and build equity, PMI may be removed under certain conditions, which can reduce your monthly housing cost.

When PMI may be removed

For many conventional loans, PMI can be removed once your loan balance reaches a certain percentage of the home’s value, often associated with improved equity. Some removals happen automatically, while others require a request and proof of value.

How equity builds over time

Equity increases as you reduce the loan balance through payments and as the property value changes. Extra payments toward principal can accelerate equity growth and potentially shorten the time until PMI removal.

How to model PMI removal with the calculator

  • Run the calculator with PMI included to estimate your current monthly cost.
  • Re-run the scenario without PMI to see how your payment changes once PMI is removed.
  • Use extra payments to test how faster principal reduction may accelerate PMI removal.

Note: PMI rules vary by loan program and lender. Always confirm eligibility, timing, and requirements for PMI removal directly with your lender.

FAQ

What is an amortization schedule?

A month-by-month breakdown showing each payment, interest vs principal, and the remaining balance after each payment.

Why is my payment mostly interest at the beginning?

Because interest is calculated on the remaining balance. Early on, the balance is highest, so the interest portion is larger.

What is escrow?

Some lenders collect taxes and insurance monthly and pay them when due. The escrow portion can change if taxes or premiums change.

Should I include taxes and insurance?

If you’re budgeting, yes—because it helps estimate the full monthly housing cost (PITI), not only principal+interest.

How do extra payments reduce interest?

Extra payments typically reduce principal faster, lowering the balance on which interest is calculated. This can reduce total interest and shorten the loan term.

What’s the difference between APR and interest rate?

Interest rate reflects the cost of borrowing principal; APR is broader and can include certain fees, helping compare offers more fairly.

Can taxes or insurance change over time?

Yes. Taxes and insurance can change due to local rates, property assessments, or premium changes, which can affect your monthly budget.

Is this calculator financial advice?

No. It provides estimates for educational purposes only. Always confirm the final numbers with your lender.

Sources & further reading

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Financial Disclaimer

This Mortgage Calculator provides informational estimates and is not a substitute for professional financial advice. Actual costs may vary based on lender terms, fees, PMI, escrow requirements, property taxes, insurance, and other factors. Always confirm final figures with your lender.