What does the Mortgage Calculator do?
It converts the entered loan assumptions into payment, interest, total cost, and schedule-style outputs using deterministic formulas.
Finance Calculator
Mortgage Calculator
Estimate a fixed-rate mortgage payment with principal, interest, taxes, insurance, mortgage insurance, HOA dues, closing costs, points, and amortization.
Last reviewed: June 21, 2026Mortgage method set v1.0.0Finance method set v1.0.0: fixed-payment, amortization, payoff, comparison, flat-rate, and simple-interest formulas
What the Mortgage Calculator does
The Mortgage Calculator estimates monthly principal and interest, optional PITI-style housing costs, loan-to-value, cash to close, total interest, and amortization for a fixed-rate home loan.
How to use the Mortgage Calculator
Enter the values that describe the loan or interest scenario, then review the result, schedule, warnings, and assumptions before using the number.
- Enter home price, down payment, rate, and term.
- Add taxes, insurance, mortgage insurance, HOA, closing costs, and points when relevant.
- Use the schedule and annual summary to see how principal and interest change over time.
Formula
Monthly P&I uses M = P x r x (1 + r)^n / ((1 + r)^n - 1). PITI adds entered taxes, insurance, mortgage insurance, and HOA.
Variables
The calculator uses the following variables in its formula layer.
- P = loan principal
- r = monthly interest rate
- n = number of payments
- M = monthly principal and interest payment
Assumptions
These assumptions keep the calculation deterministic and transparent.
- Fixed-rate reducing-balance loan.
- Taxes, insurance, PMI, HOA and closing costs are user-entered estimates.
- The calculator does not calculate official APR or lender disclosures.
Calculation steps
NexaCalc applies the formula in a fixed sequence so the output can be tested and repeated.
- Subtract down payment from home price to get loan amount.
- Calculate monthly principal and interest.
- Add entered monthly housing-cost assumptions.
- Generate amortization and annual summaries.
Worked examples
A 250,000 home with 50,000 down creates a 200,000 loan. At 6% over 30 years, principal and interest is about 1,199.10 per month.
If annual property tax is 1.2% on a 250,000 home, the monthly tax estimate is 250.00.
Closing costs and points increase cash-to-close estimates but are not treated as official lender disclosures.
Result interpretation
The headline result is an estimated monthly housing payment from the inputs, not an affordability recommendation or approval estimate.
Limitations
The result is a model, not a lender quote or official disclosure.
- Property taxes and insurance can change.
- Mortgage insurance rules differ by loan program.
- Escrow, lender rounding, daily interest, prepaid items, and APR disclosures can differ.
Mortgage-specific cost details
P&I is only the loan repayment portion. PITI-style planning adds property taxes and insurance, and many buyers also include mortgage insurance, HOA dues, points, and closing costs.
- P&I versus total monthly payment
- Down payment and LTV
- Taxes, insurance, mortgage insurance, HOA, closing costs, and points
Mortgage rate versus APR
The entered rate is the interest rate used in the payment formula. APR can include other costs under disclosure rules, so NexaCalc does not label this modeled rate as APR.
Frequently asked questions
Is the interest rate the same as APR?
No. The entered rate is used for the modeled interest calculation. APR may include other costs and lender disclosure rules.
Why can my lender's numbers differ?
Lenders can use different accrual conventions, rounding, fee timing, payment posting rules, taxes, insurance, and legal disclosures.
Does changing currency convert the amount?
No. Currency changes formatting only. NexaCalc does not fetch exchange rates or convert values.
Can I use this for approval decisions?
No. The calculator does not estimate eligibility, creditworthiness, approval probability, or suitability.
Are extra payments guaranteed to save interest?
The model applies extra payments to principal, but actual savings depend on lender prepayment terms and posting rules.
Does the schedule use daily accrual?
No. The amortization schedule uses periodic interest based on the selected frequency unless the page explicitly uses simple-interest day counts.
Is this financial advice?
No. It is a general education calculator and should be checked against lender disclosures and qualified advice when decisions matter.
What is PITI?
PITI means principal, interest, taxes, and insurance. This page can also include mortgage insurance and HOA assumptions.
Does this calculate cash to close?
It estimates down payment plus entered closing costs and points. Actual cash to close must come from lender and settlement disclosures.
References
- CFPB: Loan Estimate and mortgage disclosure education. Source.
- CFPB: Explore interest rates and mortgage costs. Source.
- CFPB: Closing Disclosure overview. Source.
- Consumer Financial Protection Bureau: loan costs, mortgage disclosures, and borrower education. Source.
- Federal Reserve consumer credit and interest-rate education resources. Source.
- U.S. Department of Education Federal Student Aid loan resources. Source.
Financial disclaimer
This calculator is for general educational use only. It is not financial, legal, tax, lending, or investment advice. Lender disclosures, compounding conventions, fees, taxes, insurance, prepayment rules, and local regulations can change actual loan costs.