Loan Calculator
Calculate loan payments, total interest, and view amortization schedules. Supports amortized loans, deferred payment loans, and bonds with various compounding frequencies.
Payment Breakdown
Amortization Schedule
Understanding Loans and Interest
A loan is a financial arrangement where a lender provides money to a borrower, who agrees to repay the principal amount plus interest over a specified period. Understanding different loan types and how interest is calculated helps you make informed borrowing decisions.
Types of Loans
Amortized Loans
The most common loan type, where each payment includes both principal and interest. Early payments are mostly interest, while later payments are mostly principal. Examples include mortgages, auto loans, and personal loans.
Deferred Payment Loans
Also known as balloon loans, these allow interest to accumulate over the loan term, with the entire principal plus accumulated interest due at maturity. Common in commercial lending and some student loans.
Bonds
Bonds work opposite to loans - you're calculating how much to pay now (present value) to receive a specific amount later. Investors use bond calculations to determine fair prices for fixed-income securities.
Key Loan Terminology
- Principal: The original amount borrowed
- Interest Rate: The cost of borrowing, expressed as a percentage
- APR (Annual Percentage Rate): Interest rate that assumes monthly compounding
- APY (Annual Percentage Yield): True annual rate accounting for compound interest
- Term: The length of time to repay the loan
- Amortization: The process of paying off debt over time through regular payments
Compound Interest
Compound interest is calculated on both the initial principal and accumulated interest. The more frequently interest compounds, the more total interest you'll pay:
Where:
- A = Final amount
- P = Principal (initial loan amount)
- r = Annual interest rate (decimal)
- n = Number of times interest compounds per year
- t = Time in years
Monthly Payment Formula
For amortized loans with fixed payments, the monthly payment is calculated using:
Where:
- M = Monthly payment
- P = Principal
- r = Monthly interest rate (annual rate / 12)
- n = Total number of payments
Secured vs. Unsecured Loans
Secured Loans
Backed by collateral that the lender can claim if you default:
- Mortgages (secured by property)
- Auto loans (secured by vehicle)
- Home equity loans
Unsecured Loans
Not backed by collateral, typically with higher interest rates:
- Personal loans
- Credit cards
- Student loans (partially)
Tip: Secured loans typically offer lower interest rates because they present less risk to lenders. However, you risk losing your collateral if you can't make payments.
Factors Affecting Loan Interest Rates
- Credit Score: Higher scores qualify for lower rates
- Loan Term: Shorter terms often have lower rates but higher payments
- Loan Amount: Very large or very small loans may have different rate structures
- Down Payment: Larger down payments can reduce rates
- Economic Conditions: Federal Reserve rates influence lending rates
- Loan Type: Secured loans typically have lower rates than unsecured
Tips for Borrowers
- Compare offers from multiple lenders
- Understand the total cost of the loan, not just monthly payments
- Consider making extra payments to reduce total interest
- Review the amortization schedule to understand how payments are applied
- Check for prepayment penalties before paying off a loan early
- Improve your credit score before applying for significant loans