Enter a purchase price, down payment, fixed interest rate, term, and recurring housing costs. The result separates principal and interest from taxes, insurance, HOA dues, modeled mortgage insurance, and optional extra principal, then shows how the balance changes over time.
Mortgage & Loans calculator Content updated 2026-08-16Calculations run privately in your browser
Cindy Zhang and Heather Kincaid co-authored the plain-language explanation of the fixed-rate amortization method, housing-cost inputs, worked example, schedule interpretation, limitations, and links to the cited Consumer Financial Protection Bureau resources. This is an editorial authorship scope, not a claim of lending, underwriting, legal, tax, financial-planning, or other professional review.
The byline does not claim professional credentials, trade, finance, insurance, actuarial, underwriting, or claims experience, licensed review, or independent professional review for either author.
Enter mortgage assumptions
Example values are prefilled
How to use this mortgage calculator
Estimate fixed-rate mortgage principal and interest, recurring housing costs, extra-payment payoff time, rate sensitivity, and a monthly or annual amortization schedule.
Formula
Loan principal = price − down payment. Monthly principal and interest = P × r ÷ [1 − (1 + r)^−n]. Estimated monthly total adds entered tax, insurance, HOA dues, modeled mortgage insurance, and extra principal.
Quick example
Example: A $400,000 home with $80,000 down creates a $320,000 principal. At 6.5% for 30 years, principal and interest are about $2,023 per month before taxes, insurance, HOA dues, or extra principal.
Accuracy and limitations
The model assumes a fixed rate and regular monthly payments. It does not calculate APR, points, lender fees, closing costs, escrow adjustments, daily interest, adjustable rates, buydowns, recasting, or lender-specific mortgage-insurance rules.
CFPB: Loan Estimate Explainer — Official guide to the interest rate, projected payments, closing costs, and cash-to-close fields on a Loan Estimate
CFPB: Shopping for a Mortgage — Current consumer guidance for comparing terms, rates, payments, fees, and early-payment provisions
Choose and verify your inputs
Purchase price and cash down
Start with the signed or negotiated purchase price, then enter only the cash that will reduce principal as the down payment. Keep lender fees, prepaid taxes, insurance deposits, points, and other closing costs outside the down-payment field because this calculator does not finance or itemize them.
Rate and repayment term
Copy the fixed note rate and repayment term from a current Loan Estimate when one is available. The note rate drives principal-and-interest amortization; APR includes certain finance charges and should not be substituted into this payment formula.
Property-specific recurring costs
Use parcel-specific property tax data, a property-specific annual insurance quote, and current HOA documents. These recurring costs do not reduce the loan balance and can change after closing even when principal and interest are fixed.
Mortgage insurance
Enter a mortgage-insurance rate only as a planning estimate supplied by a lender. The calculator's below-20-percent trigger is deliberately simplified and cannot reproduce loan-program eligibility, premium schedules, removal dates, or lender-specific rules.
How the calculation works
Find the starting principal
Subtract the entered down payment from the purchase price. Closing costs and other cash-to-close items are not included in this principal calculation.
Calculate principal and interest
Convert the annual fixed rate to a monthly rate and apply the standard level-payment amortization formula across the entered number of monthly payments.
Build the monthly housing estimate
Convert annual property tax and homeowners insurance to monthly amounts, then add HOA dues and the simplified mortgage-insurance estimate to principal and interest.
Model optional extra principal
Apply the entered recurring extra amount to principal after each scheduled payment to estimate an earlier payoff and lower total interest, subject to the calculator's stated assumptions.
Group the amortization schedule
Track each payment's interest, principal, and remaining balance. The monthly view retains individual modeled payments, while the annual view groups those same rows into year-level totals without changing the arithmetic.
Worked calculation: Consider a $400,000 purchase with $80,000 down, a 30-year fixed loan at 6.5%, $4,800 in annual property tax, $1,800 in annual homeowners insurance, no HOA dues, and no extra principal.
Subtract the $80,000 down payment from $400,000 to obtain a $320,000 starting principal.
Apply the monthly amortization formula at 6.5% for 360 payments to estimate about $2,023 in monthly principal and interest.
Convert $4,800 of annual tax to $400 per month and $1,800 of annual insurance to $150 per month.
Add $2,023, $400, and $150. With a 20% down payment, no entered HOA dues, and no modeled mortgage insurance, the estimated monthly total is about $2,573.
Across the first 12 scheduled payments, about $20,694.69 goes to interest and $3,576.72 to principal, leaving an estimated $316,423.28 balance after one year.
Result: The example separates the approximately $2,023 contractual principal-and-interest payment from roughly $550 of entered recurring property costs. It still excludes closing costs, maintenance, repairs, utilities, and changes in tax or insurance.
Next step: Replace every example value with figures from a current Loan Estimate, parcel record, insurance quote, and HOA documents, then compare both monthly total and cash to close across offers.
Interpret the result
Principal and interest
This is the fixed loan-payment portion under the entered rate and term. It excludes every recurring housing cost and every closing cost.
Estimated monthly total
Use this broader figure for an initial housing budget because it combines the modeled loan payment with entered taxes, insurance, HOA dues, and applicable mortgage insurance.
Interest and payoff
Total interest is a model of scheduled borrowing cost if assumptions remain unchanged. An extra-principal scenario is useful only if the additional amount is affordable and the servicer applies it as intended.
Rate sensitivity
Compare nearby rates to understand how an unlocked rate or alternate offer could change the payment. A smaller payment alone does not reveal differences in fees, points, or total cash required.
Amortization schedule
Early fixed-rate payments generally allocate more to interest and later payments more to principal. Use the remaining-balance column to audit the modeled payoff, not as a lender payoff quote for a particular date.
Common mistakes to avoid
Entering APR in the interest-rate field instead of the fixed note rate used for amortization.
Treating the down payment as all cash due at closing and overlooking lender fees, prepaid items, reserves, inspections, and moving costs.
Comparing only principal and interest while omitting property tax, insurance, HOA dues, mortgage insurance, maintenance, and utilities from the household budget.
Using a statewide tax average or generic insurance estimate when parcel records and a property-specific quote are available.
Assuming mortgage insurance ends automatically at exactly 20% equity or that every extra payment is applied immediately to principal.
Decision checklist
Compare the calculator result with the principal-and-interest and estimated-total-payment sections of each written Loan Estimate.
Confirm the property tax record, insurance quote, HOA dues, special assessments, and mortgage-insurance terms before relying on the monthly total.
Keep closing costs and an emergency reserve separate from the cash entered as the down payment.
Test a higher-rate case and higher tax or insurance case to see whether the payment remains manageable.
Ask the lender or servicer how optional extra payments are credited and whether the loan has any prepayment restriction.
Frequently asked questions
Does the result include closing costs?
No. Add lender, title, recording, prepaid, inspection, appraisal, legal, and other closing costs separately using a written estimate.
Why can my lender's payment differ?
Payment dates, rounding, escrow estimates, mortgage insurance, fees, rate locks, and loan-program rules can differ from this simplified model.
Do extra payments always shorten the loan?
They generally do when applied promptly to principal and no prepayment restriction applies. Confirm instructions with the loan servicer.
Should I enter the interest rate or APR?
Enter the fixed note rate used to amortize principal and interest. APR incorporates certain costs for comparison and is not the rate used by this simplified payment formula.
Does the monthly total include maintenance and utilities?
No. It includes only principal and interest plus the tax, insurance, HOA, mortgage-insurance, and extra-principal inputs shown. Budget separately for repairs, maintenance, utilities, and other ownership costs.
When does the calculator include mortgage insurance?
It applies the entered annual rate when the down payment is below 20% of purchase price. Actual mortgage-insurance requirements, premiums, and cancellation rules depend on the loan program and lender.
Can I use the result to compare lenders?
Use it as an arithmetic cross-check, then compare official Loan Estimates for rate, APR, payment changes, closing costs, lender credits, cash to close, and loan features.
