Loan Payment and Interest Calculator

What Is a Loan Calculator?

A loan calculator estimates the payments required to repay borrowed money over a selected period. By comparing the loan amount, interest rate, repayment term, compounding method, and payment frequency, you can see how different assumptions affect the amount paid each period and the total cost of borrowing.

This calculator is designed primarily for standard fixed-rate amortized loans. Common examples include personal loans, auto loans, student loans, and other installment loans. Your lender's actual offer may differ because of fees, rate conventions, and contract terms.

If you are estimating a home purchase, use our Mortgage Calculator. For vehicle financing, compare your figures with the Car Payment Calculator. You can also use the Credit Card Payoff Calculator for revolving credit balances.

How to Use the Loan Calculator

Enter your loan details, then select Calculate Loan to update the results. The calculator keeps edited inputs separate from the last calculated results so you can make changes and compare scenarios deliberately.

• Loan amount: Enter the principal you plan to borrow, before interest and any additional fees.
• Loan term: Set the number of years and any additional months in the repayment period.
• Interest rate: Enter the annual rate as a percentage. Use the rate convention that best matches the loan terms you are evaluating.
• Compounding: Choose monthly (nominal APR compounded monthly) or annually (effective annual rate).
• Payment frequency: Choose weekly, every two weeks, monthly, quarterly, or annually. The number of scheduled payments changes with this selection.

After calculating, review the payment amount alongside total payments and total interest. A lower payment does not automatically mean a cheaper loan: compare the total cost and the length of time you will be repaying the balance.

What Does the Loan Calculator Show?

The results summarize the selected loan scenario, including:

• Periodic payment: The estimated amount due each selected payment period.
• Number of payments: The estimated number of scheduled payments over the selected term.
• Total payments: The sum of the scheduled payments over the full term.
• Total interest: The estimated borrowing cost above the original principal.
• Principal and interest breakdown: A visual comparison of the amount borrowed and the estimated interest.
• Amortization schedule: A period-by-period view of payment, interest, principal reduction, and remaining balance.

Loan Payment Formula

For a fixed-rate amortized loan with a non-zero periodic interest rate, the scheduled payment is calculated using the principal, the interest rate per payment period, and the total number of payments:

In this formula:

• P is the original loan principal.
• r is the interest rate per payment period, expressed as a decimal.
• n is the total number of scheduled payments.

The entered annual rate must first be converted to a periodic rate using the selected compounding method and payment frequency. At a 0% rate, the formula simplifies to the principal divided by the number of scheduled payments.

Example Loan Calculation

Suppose you borrow $25,000 at an annual interest rate of 7% for 5 years, with monthly payments and monthly compounding. Under the standard fixed-rate amortization formula, the estimated payment is approximately $495.03 per month.

Across 60 scheduled payments, the total repaid would be approximately $29,701.80, including about $4,701.80 in interest. These are illustrative estimates and exclude fees or other charges. Different rate conventions or payment schedules can produce different results.

Principal vs. Interest

Principal is the original amount borrowed. Interest is the amount charged for borrowing that money. With an amortized loan, each payment generally covers the interest accrued for that period and pays down part of the outstanding principal.

Early payments may contain a larger interest portion because the balance is higher. As the principal decreases, the interest charged per period generally falls and more of each level payment goes toward principal. The exact allocation depends on the rate and payment schedule.

How Interest Rate Affects Loan Cost

When the principal and term stay the same, a higher interest rate generally increases both the scheduled payment and total interest. Even a modest rate difference can have a meaningful effect over a multi-year repayment period.

To compare scenarios, change only the interest rate while keeping the other inputs unchanged. You can also explore the Interest Calculator to better understand how interest affects financial calculations.

How Loan Term Affects Payments

A longer repayment term spreads the principal across more scheduled payments and generally reduces each payment. However, the balance remains outstanding for longer, so the total interest can be higher. A shorter term usually requires larger payments but can reduce the total interest paid when other assumptions remain the same.

Compare both the periodic payment and the total repayment amount before deciding which term fits your budget. The estimate does not determine loan eligibility or account for your full financial situation.

What Is an Amortized Loan?

An amortized loan is repaid through scheduled payments over a defined period. Payments are applied to interest and principal, with the outstanding balance declining as principal is repaid. Many personal, auto, student, and mortgage loans use amortization, although the contract details can vary.

Review the amortization schedule to see how the balance changes over time. It is an estimate based on the values entered, not a substitute for the lender's official repayment schedule.

Compounding and Payment Frequency

Compounding describes how the annual interest rate is represented when converting it to the rate used for each payment period. This calculator offers a nominal annual rate compounded monthly and an effective annual rate. These conventions are not interchangeable, so use the rate definition supplied with the loan you are comparing.

Payment frequency controls how often a payment is scheduled. Monthly payments occur 12 times a year, biweekly payments 26 times, weekly payments 52 times, quarterly payments 4 times, and annual payments once. Real lenders may use different day-count rules, rounding, or payment timing; this calculator provides a simplified comparison.

Important Limitations

This calculator provides estimates for a fixed-rate amortized loan using the entered values and selected rate and payment conventions. It does not include origination fees, taxes, insurance, penalties, variable-rate changes, missed payments, or every lender-specific rule. The calculated payment and amortization schedule may differ from your lender's figures because of rounding and contract terms. Use the results for planning and comparison, not as a loan offer or financial advice.

Related Loan and Finance Calculators

Continue comparing borrowing scenarios with the Mortgage Calculator, Car Payment Calculator, Credit Card Payoff Calculator, or Compound Interest Calculator.

Frequently Asked Questions