Free Loan Repayment Calculator

What This Loan Repayment Calculator Can Do

A loan repayment calculator—often called a loan payoff calculator, monthly payment calculator, or loan amortization calculator—lets you quickly explore different ways to repay borrowed money and choose the option that fits your budget. Whether you are financing a home, buying a car, consolidating debt, or covering school expenses, this tool works as both a personal loan calculator and a mortgage payoff calculator. It displays a detailed loan repayment schedule in both table and chart form, showing exactly how each payment splits between interest and principal. If you make extra payments, the tool recalculates the term and total interest, making it an effective extra payment calculator for anyone who wants to become debt‑free faster.

Understanding Loan Repayment

When you take out a loan, you receive a lump sum and agree to return it over a set period, plus interest. Repayments usually start soon after the loan is issued and are made in regular (often monthly) installments. Each installment consists of two parts:

• Interest – the cost of borrowing, calculated on the remaining balance.
• Principal – the portion that reduces the original debt.

If the loan is fully paid off by the end of its term, it is considered fully amortized. Some loans are only partially amortized, requiring a large final payment (a balloon payment) to settle the remaining balance.

Three Common Repayment Schedules

To illustrate the main repayment structures, the calculator uses a base example:

• Loan amount: $10,000
• Loan term: 10 years (120 months)
• Annual interest rate: 7.5% compounded monthly
• No extra payments

1. Even Total Payments (Standard Amortization)

This is the default schedule for mortgages, car loans, and many personal loans. The monthly payment stays the same throughout the term. In the beginning, most of the payment goes toward interest; gradually the interest portion declines and the principal portion grows, causing the outstanding balance to decrease faster over time.

For the base example, the monthly payment is $118.70.

• First year: total interest = $726.33, principal paid =$698.09
• Last year: principal paid = $1,368.20, interest =$56.22
• Total paid over 10 years: $14,244.21 ($10,000 principal + $4,244.21 interest)

2. Even Principal Payments

Under this schedule, the principal amount is the same every month ($10,000 ÷ 120 =$83.33). Interest is recalculated each month on the remaining balance, so it steadily decreases. As a result, the total monthly payment declines over the loan’s life.

Using the same $10,000 loan:

• First year: total payments = $1,715.63 ($715.63 interest, $1,000 principal)
• Tenth year: total payments = $1,040.63 ($40.63 interest, $1,000 principal)
• Total interest paid over the term: $3,781.25 – lower than the even‑payment schedule because more principal is retired early.

3. Balloon Payment Loan

In this structure, monthly payments are calculated as if the loan will be fully amortized over a longer period (e.g., 20 years), keeping each payment low. However, after a specified number of years (the balloon date), the entire remaining principal plus any accrued interest must be paid in one lump sum.

For the base example, with a 20‑year amortization and a balloon after 10 years:

• Monthly payment (first 10 years): $80.56
• Balloon payment at year 10: $6,824.60
• Total interest over those 10 years: $6,453.82

This option suits businesses or investors who expect higher future cash flows but need modest payments in early periods.

Comparing the Three Schedules

The table below summarizes the key differences for the $10,000, 10‑year (or 20‑year/balloon) example:

Feature	Even Total Payment	Even Principal Payment	Balloon Payment
Loan term (amortization)	10 years	10 years	20 years (balloon at 10 yrs)
Monthly payment pattern	Constant, $118.70	Decreasing (starts ~$145, ends ~$1,041)	Constant, $80.56 until balloon
Monthly principal	Increases over term	Constant, $83.33	Increases over term
Total interest paid over 10 years	$4,244.21	$3,781.25	$6,453.82

The even principal schedule produces the lowest total interest because a larger portion of the debt is repaid early. The balloon schedule results in the highest interest because the bulk of the principal remains unpaid for many years.

How Extra Payments Help

Any amount you pay above the required monthly installment reduces the principal directly. This accelerates the decline of the unpaid balance, cuts the total interest, and shortens the loan term. The calculator includes an “Extra monthly repayment” field so you can see the effect immediately – a few extra dollars each month can save hundreds or thousands in interest and shave months off the loan.

The Formula Behind the Payments

For a standard amortized (even total payment) loan, the monthly payment is calculated using:

$$P = \dfrac{A \times r \times (1 + r)^n}{(1 + r)^n - 1}$$

where:

• $P$ = monthly payment
• $A$ = loan principal
• $r$ = periodic interest rate (annual rate ÷ 12)
• $n$ = total number of payments (months)

The unpaid balance after $k$ payments can be found with:

$$B = A \times (1 + r)^k - \dfrac{P}{r} \times \left((1 + r)^k - 1\right)$$

For even principal schedules, the monthly principal is simply $A / n$, and the interest for month $t$ is:

$$\text{Interest}_t = \left( A - (t-1) \times \frac{A}{n} \right) \times r$$

Important Notes

All computed values are approximate due to rounding. The calculator is intended for educational and advisory purposes and should not replace professional financial advice. Always confirm terms with your lender before making a commitment.