Mortgage Interest Calculator: Total & Monthly Interest

Loan inputs

Loan amount Principal borrowed. Interest rate (APR)

Annual nominal rate.

Loan term

years

Typical: 15 or 30 years. Start date Used for payoff month/year.

Extra monthly payment (optional) Applied to principal each month. Interest period (months) Interest paid in first N months (default 12).

Results

Interest breakdown + savings preview.

Monthly payment (P&I)

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Interest in first payment

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Interest paid in first 12 months

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Total interest (no extra)

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Total interest (with extra)

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Interest saved (extra vs none)

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Payoff date (no extra)

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Payoff date (with extra)

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Interest preview (first 12 payments)

#	Date	Payment	Principal	Interest	Balance
Run a calculation to see the schedule.

Note: Table shows P&I only (interest/principal). Extra payments increase principal paid.

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