Skip to content

Mortgage toolkit

Payments · amortization · refinance

30-Year Fixed Mortgage Calculator

Pre-filled for a 30-year fixed loan. Inspect monthly vs yearly amortization, extra payments, and long-run interest cost.

Loan inputs

Results update as you type. For education only — verify with your lender.

Adds to principal after your scheduled payment — models early payoff and interest savings.

Refinance comparison

Closing costs are rolled into the new loan balance for the new payment estimate.

Loan comparison

Three side-by-side scenarios (P&I only).

Option Amount Rate % Years
A
B
C
Scenario Monthly P&I Total paid Total interest

Affordability & DTI helper

Back-end DTI cap with a static monthly taxes + insurance estimate.

Rent vs buy (simplified)

Renting

Buying

Inflation impact (real cost)

Mortgage interest tax deduction (illustrative)

Not tax advice — uses your main amortization schedule.

Year Interest paid Est. tax savings

ARM simulator (simplified)

Fixed introductory rate, then a single fully-indexed rate for remaining term — uses main loan amount & term.

Amortization schedule

# Principal Interest Balance

Principal vs interest (cumulative)

How mortgage payments work

Most fixed-rate loans use a level payment: your scheduled principal-and-interest payment stays the same, but the split changes. Early payments are mostly interest; later payments mostly pay down principal. This calculator uses the standard amortization formula so you can see that shift month by month.

What is amortization?

Amortization is the process of paying off debt over time with scheduled payments. Each payment covers interest accrued since the last payment, with the remainder reducing principal. The amortization schedule tabulates those amounts and the remaining balance after every payment.

How interest affects your loan

Interest accrues on the outstanding balance, not the original purchase price. That is why extra principal payments — even modest ones — can reduce total interest dramatically: they lower the balance earlier, so less interest compounds over the life of the loan.

15-year vs 30-year tradeoffs

Shorter terms usually mean higher monthly payments but less total interest and faster equity. Longer terms improve cash flow but increase lifetime interest — compare scenarios with the loan comparison tool above.

Disclaimers

This tool provides estimates for education and planning. Actual lender pricing, escrow, mortgage insurance, HOA, and regulatory requirements are not modeled. Tax and investment guidance requires a qualified professional.