Loan Repayment Calculator

WHAT IT DOES

Loan Repayment Calculator helps you understand the true cost of borrowing. Enter the loan amount, annual interest rate, and loan term in months — the panel instantly shows your monthly payment, total interest paid over the life of the loan, and the total repayment amount. The amortization schedule breaks down every payment into principal and interest components, showing exactly how your balance decreases over time. This transparency helps you make informed decisions about borrowing, refinancing, or comparing different loan offers.

WHERE IT RUNS

This script runs on every website you visit. Whether you are researching mortgage options on bank websites, comparing auto loans on finance portals, evaluating student loan repayment plans, or planning a business loan in a financial application, the panel is always available. It works alongside your existing tools without interfering with your workflow.

HOW TO USE

Enter the loan amount in the first field, the annual interest rate as a percentage in the second field, and the loan term in months in the third field. Results update automatically as you type. Click "Show Amortization Schedule" to see a detailed breakdown of each monthly payment, including how much goes toward principal versus interest. The schedule displays the first 60 months, with an indicator for any remaining months. Click any history entry to reload previous calculations for quick comparisons. Use the "Copy Result" button to copy the monthly payment and total repayment to your clipboard.

THE COMPOUND INTEREST MECHANISM

Loan Repayment Calculator uses the standard amortization formula that banks and financial institutions actually use: M = P * (r(1+r)^n) / ((1+r)^n - 1), where M is the monthly payment, P is the principal, r is the monthly interest rate, and n is the number of payments. The calculator handles edge cases correctly — when the interest rate is zero, it falls back to simple division. All financial values are rounded to two decimal places using standard rounding rules to match real-world currency handling. The amortization schedule is generated dynamically using the same formula, ensuring consistency between the summary results and the detailed breakdown.

THE PANEL

The panel is fully draggable and remembers its position per site. It minimizes to a compact floating bubble when collapsed. All settings — default interest rate, default loan term, and calculation history — persist across browser sessions using GM_setValue storage. Press the Escape key to close the panel. The panel automatically focuses the loan amount input field for quick keyboard entry.

PLEASE NOTE

This script requires the free BotGentz extension to run. The calculations are estimates based on standard amortization formulas — actual loan terms may vary by lender, fees, and specific conditions. Always verify with your financial institution before making decisions. Websites change their structure and behavior over time; if any functionality stops working, the script may need an update. No user data is sent anywhere — all calculation history and settings are stored locally in your browser. The script never reads or modifies password, hidden, or file input fields.