Mortgage Calculator
Model mortgage payments, entered housing costs, extra principal, and scheduled rate changes.
Your input never leaves your device.
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Everything runs 100% locally in your browser. No files are uploaded to any server.
Formula
P&I = P × r ÷ [1 − (1 + r)^−n], or P ÷ n at 0%. Add entered property tax, homeowners insurance, HOA, mortgage insurance, and extra principal. Recalculate P&I from the remaining balance/term at each user-entered rate change.
Worked example
A 300,000 loan at 6.5% for 30 years starts at about 1,896.20 per month for principal and interest. Entering 3,600 yearly property tax, 1,200 yearly insurance, and 100 monthly HOA gives an initial housing cost of about 2,396.20 before any mortgage insurance or extra principal.
What the result means
Supports financed/upfront fees, extra principal, mortgage-insurance duration, and explicit future rate scenarios. Taxes/insurance stay constant; this is not a quote, APR calculation, or prediction of future rates.
How to Use Mortgage Calculator
Enter the requested values
Provide the inputs for this mortgage calculator. Use consistent units where applicable.
Read the estimated housing payment
The result recalculates as you edit the inputs.
Check the mortgage calculator assumptions
Use the mortgage calculator formula and notes below to understand what is—and is not—included.
Key Features & Benefits
Formula and worked example
A 300,000 loan at 6.5% for 30 years starts at about 1,896.20 per month for principal and interest. Entering 3,600 yearly property tax, 1,200 yearly insurance, and 100 monthly HOA gives an initial housing cost of about 2,396.20 before any mortgage insurance or extra principal.
Clear scope
Supports financed/upfront fees, extra principal, mortgage-insurance duration, and explicit future rate scenarios. Taxes/insurance stay constant; this is not a quote, APR calculation, or prediction of future rates.
Frequently Asked Questions
Are taxes and insurance included?
Yes, when you enter them. Values left at zero are excluded.
Can I model changing rates?
Enter the month and rate for each change. The schedule recalculates payments over the remaining original term; future rates and contract caps must be supplied by you.
Does extra principal reduce interest?
Yes. Extra payments reduce the outstanding balance and can shorten the modeled payoff.
Key terms
- mortgage calculator
- Supports financed/upfront fees, extra principal, mortgage-insurance duration, and explicit future rate scenarios. Taxes/insurance stay constant; this is not a quote, APR calculation, or prediction of future rates.