Back to Free Tools
FREE TOOLS
Extra Payment Loan Payoff Calculator
Compare a fixed-rate loan schedule with recurring and one-time extra principal payments.
Remaining loan principal, Nominal annual interest (%), Remaining term (months), Extra principal each month, One-time extra principal, Month of one-time payment
JSON
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Enter the labelled values using the displayed units and explicit assumptions.
- Choose Calculate result and review the complete report and any undefined or no-solution states.
- Choose Download result to save the complete JSON. Reset clears the result and restores example controls.
Examples
Remaining loan principal: 20000
Nominal annual interest (%): 6
Remaining term (months): 60
Extra principal each month: 100
One-time extra principal: 1000
Month of one-time payment: 12
Limitations
- Monthly interest before end-of-month payment. Positive principal,annual nominal rate0–100%,term1–1200months. Extra principal nonnegative;one-time amount applies in the selected month. No fees,penalties,daily accrual or cent-rounding ledger. Complete baseline and accelerated schedules.
- Scalar controls accept explicit finite decimal syntax;positive values normally1e-12–1e12,nonnegative0–1e12 unless a narrower range is stated. JSON numeric rows use finite IEEE754 values within their stated bounds. Derived counts above1billion and nonfinite results refuse. Combined input<=400000UTF8 bytes;complete JSON<=4MiB. All processing stays in your browser.
Related tools
No items found.