Mortgage Calculator
Estimate principal & interest with optional monthly tax and insurance line items you control.
For educational purposes only. This calculator does not provide financial advice. Actual loan terms may vary by lender.
📊 Visual Analysis
What This Calculator Does
This Mortgage Calculator builds a simplified PITI-style monthly estimate: principal & interest on the financed amount, plus monthly allocations for property tax and homeowners insurance that you enter. It subtracts your stated down payment from the home price to get the loan principal, amortizes that principal at a fixed annual rate over the loan term, then adds one-twelfth of your annual tax and insurance inputs. Results are educational projections only — not a Loan Estimate, not a lender quote, and not a prediction of approval or future housing costs.
Formula
1) Financed principal
2) Principal & interest (level payment) with fixed monthly rate r = annual rate ÷ 12 ÷ 100 and n = term in months:
3) Monthly tax & insurance (user-supplied annual amounts spread evenly):
4) Total monthly (PITI-style here): PI + Taxmo + Insmo. HOA dues, PMI, and escrow true-ups are not modeled.
Input Fields Explained
Home Price ($)
The purchase price or valuation you want to stress-test. It should match the scenario you are modeling, not necessarily the appraisal or list price you will receive from a seller or lender.
Down Payment (%)
Upfront equity as a percent of the home price. A larger down payment reduces the financed principal and usually lowers both PI and lifetime interest (all else equal). Eligibility rules vary by lender and program.
Interest Rate (%)
Annual interest rate you choose for modeling. It is not a recommendation and not a forecast of available rates. For adjustable-rate products, this single-rate path is only a snapshot.
Loan Term (years)
Amortization horizon in years (converted to months internally). Longer terms usually lower PI but increase total interest paid.
Annual Property Tax ($)
Your assumed annual property tax bill, divided by 12 for the monthly line item. Real bills depend on mill rates, exemptions, reassessments, and escrow timing.
Annual Insurance ($)
Your assumed annual homeowners insurance premium, divided by 12. Actual premiums vary by coverage, carrier, and property risk factors.
Example Calculation
Illustration only (numbers are for math walk-through, not market guidance): Home price $400,000, down 20%, rate 6.5% annual, 30 years, annual tax $4,800, annual insurance $1,800.
L = 400,000 − 80,000 = $320,000
Monthly tax = 4,800 ÷ 12 = $400; monthly insurance = 1,800 ÷ 12 = $150
Use the live calculator for the exact PI and total; the tool sums PI + tax + insurance for the headline monthly figure.
Assumptions: Fixed rate for the full term, level payments, no PMI, no HOA, no closing costs, no prepayments. Rounding may differ from your lender.
How to Read the Result
Cash equity required at closing (down) and principal financed (price minus down). The PI payment is computed on the loan amount only.
The amortizing loan payment portion before taxes and insurance.
Monthly slices of the annual figures you entered. If you leave them at zero, the total reflects PI only.
PI plus the monthly tax and insurance assumptions. Compare this to your budget; it is still not your full housing cost if HOA, utilities, or maintenance apply.
Interest portion accumulated over the modeled fixed-rate schedule on the loan principal (tax and insurance are not “interest” in this summary line).
Common Mistakes
- Forgetting PMI or HOA. Many borrowers have additional recurring charges not captured here.
- Assuming taxes stay flat. Reassessments and rate changes can move the tax line item year to year.
- Treating the output as an approval. Underwriting, credit, appraisal, and program rules determine eligibility and final pricing.
- Using escrow confusion. Lenders may collect tax and insurance through escrow with periodic adjustments; your inputs are static for this model.
- Expecting ARM paths. A single fixed rate for the whole term does not simulate future rate resets.
When This Calculator Is Useful
- Comparing how different down payments and loan terms change PI and total interest
- Seeing how optional tax and insurance assumptions change a monthly budget figure
- Walking through a fixed-rate scenario before discussing numbers with a loan officer
Limitations
- Fixed-rate amortization only; adjustable-rate behavior is not modeled month by month
- No PMI, no HOA, no closing costs, no points, no lender credits
- Tax and insurance are static user guesses, not pulled from county records or carriers
- Does not replace a Loan Estimate, Closing Disclosure, or professional advice
- Does not predict future home values, insurance renewals, or tax policy changes
- Educational estimates only
Frequently Asked Questions
What does PITI mean in this calculator?
PITI usually stands for Principal, Interest, Taxes, and Insurance. This tool explicitly models principal & interest from your loan inputs and adds monthly portions of the annual property tax and insurance fields you provide. It does not automatically add other common components such as HOA dues or PMI.
Does this include HOA fees or PMI?
No. HOA dues and private mortgage insurance depend on the property, association rules, and loan-to-value and program requirements. If they apply to you, add separate budget lines after you review your lender disclosures.
Why might my lender’s payment differ from this estimate?
Lenders may round differently, collect escrow with periodic adjustments, use actual tax certificates, include mortgage insurance, or apply promotional pricing and fees. This page is a fixed-rate math illustration for the numbers you enter, not a substitute for a Loan Estimate.
Is the interest rate shown a recommendation of what I should pay?
No. The rate field is a modeling input only. Your offered rate depends on credit profile, loan program, points, market conditions, and lender pricing. Use sensitivity checks with different rates rather than treating any single input as guidance.
Can I use this for an adjustable-rate mortgage (ARM)?
Only as a rough snapshot. The amortization uses one constant annual rate for the entire term. ARM payments can change when the index and margins reset, which this calculator does not simulate over time.
Does this calculator guarantee loan approval?
No. Approval depends on income verification, credit history, debt-to-income limits, appraisal, and lender policies. The results here are educational projections based solely on the values you supply.
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Educational Disclaimer
This calculator is for educational and informational purposes only. It does not provide investment, financial, tax, or legal advice. The results are based on the inputs and assumptions you provide and may not reflect real market conditions, fees, taxes, or risks. Always do your own research or consult a qualified professional before making financial decisions.