Fixed Projection Tool

Version 4.0.1

Project a fixed-rate mortgage balance, interest, principal, taxes, and extra principal payments over time.

Budgeting estimate only. This tool is not legal, tax, or financial advice. Outputs are rough projections based on user-entered assumptions and should not be treated as a lender payoff quote or guaranteed result.

Loan basics

Original mortgage amount

Current principal balance

Mortgage start date

Projection start date

First scheduled payment date

Original term years

Fixed interest rate %

Base monthly P&I

Auto-calculate base P&I from original amount, rate, and term

For a fixed-rate loan, the scheduled P&I stays constant unless the loan pays off early. Current principal balance is the balance used at the projection start date.

Property tax

Property tax amount

Tax frequency

Tax is included in cash-flow views, not in loan balance amortization.

Additional principal

Additional monthly payment amount

Start date

End date

Single extra principal payment

Single payment date

Extra payments are applied directly to principal and can shorten the payoff timeline.

Views / scenarios

Chart view

Scheduled-only projection

With additional principal

Key

Scheduled-only projectionBase amortization without additional principal inputs.

With additional principalApplies monthly and single extra principal assumptions.

Scheduled-only ignores all extra principal fields. With additional principal applies the monthly and single extra payment settings.

Save / export

Save/load stores visible inputs and settings as a local JSON file. CSV and PDF exports use the current settings and visible scenarios.

Projection summary

Methodology

The fixed-rate projection uses the entered current balance, fixed annual rate, scheduled P&I, and remaining scheduled payments. Interest accrues monthly as balance × annual rate ÷ 12. Extra principal reduces balance after scheduled principal is applied. Property tax appears only in cash-flow views and does not affect amortization.