Loan Repayment Calculator

What This Calculator Does

This loan repayment calculator estimates your fixed monthly payment, total interest paid over the life of the loan, and a full amortization schedule. It works for personal loans, auto loans, student loans, and other fixed-rate installment loans. You provide the loan amount, annual interest rate, and loan term, and the calculator returns a clear breakdown of your repayment obligations.

How the Calculation Works

The calculator uses the standard amortization formula for fixed-rate loans:

M = P × [r(1 + r)^n] / [(1 + r)^n – 1]

Where:

• M = monthly payment
• P = principal loan amount
• r = monthly interest rate (annual rate divided by 12)
• n = total number of monthly payments (loan term in years × 12)

Each payment is split between interest and principal. Early payments go mostly toward interest. Over time, more of each payment applies to the principal balance. The calculator accounts for this shift automatically and shows the full amortization path.

How to Use the Calculator

1. Enter the loan amount – the total you plan to borrow.
2. Enter the annual interest rate – as a percentage (e.g., 6.5 for 6.5%).
3. Enter the loan term – in years (e.g., 5 for a five-year loan).
4. Click calculate – the results show your monthly payment, total interest, and total repayment amount.

All inputs are required. The calculator assumes payments are made monthly and the interest rate remains fixed for the entire term.

Understanding Your Results

Monthly Payment

This is the fixed amount you will pay each month for the entire loan term. It does not include fees, insurance, or taxes that may be added by your lender.

Total Interest Paid

The cumulative interest cost over the full loan term. This number shows the true cost of borrowing beyond the principal amount.

Total Repayment

The sum of all monthly payments, which equals the principal plus total interest. This is the total amount you will have paid by the end of the loan term.

Amortization Schedule

A period-by-period breakdown showing the payment number, payment amount, interest portion, principal portion, and remaining balance. Use this to see exactly how your loan balance decreases over time.

Common Mistakes to Avoid

• Using the wrong rate – Enter the annual interest rate, not the monthly rate. The calculator handles the conversion automatically.
• Confusing term length – Enter the loan term in years, not months. For example, a 60-month loan is 5 years.
• Ignoring additional costs – The calculator shows principal and interest only. Actual loan payments may include origination fees, insurance, or taxes that increase your monthly obligation.
• Assuming the rate is fixed – This calculator is designed for fixed-rate loans. Variable-rate loans will produce different results if rates change.

Limitations

• Assumes a fixed interest rate for the entire loan term.
• Does not account for fees, prepayment penalties, or late payment charges.
• Assumes payments are made on time every month.
• Does not support interest-only or balloon payment structures.
• Results are estimates. Always confirm with your lender before making financial decisions.

Practical Use Cases

• Comparing loan offers – Enter different rates and terms to see how they affect your monthly payment and total interest.
• Budget planning – Determine if a monthly payment fits within your budget before applying for a loan.
• Refinancing analysis – Compare your current loan terms against a potential refinance to see if the savings justify the switch.
• Understanding amortization – See how extra payments would reduce total interest and shorten the loan term.