FinanceCalcs
Loan Calculator
Calculate your monthly payment, total interest, and full amortization schedule for any loan — and see exactly how much of each payment goes toward principal versus interest over the life of the loan.
Works for personal loans, student loans, auto loans, mortgages, and any fixed-rate installment loan.
Loan Calculator
Total Interest: $0 | Total Cost: $0
Monthly Payment: $0
- Balance Remaining
- Total Paid
"Annual income twenty pounds, annual expenditure nineteen and six, result happiness."
— Charles Dickens, David Copperfield
What is a loan calculator?
A loan calculator helps you determine the monthly payment on any fixed-rate loan — personal, auto, student, mortgage, or business — based on the loan amount, interest rate, and repayment term. It takes the guesswork out of borrowing by showing you the full cost before you commit.
Under the hood, it uses amortization math to calculate exactly how much of each payment goes toward interest versus reducing the principal. Early in the loan, a larger share goes to interest; as the balance falls, more of each payment pays down principal. The full amortization schedule makes this visible month by month.
Knowing your monthly payment and total interest cost upfront lets you compare loan offers side by side and make an informed borrowing decision before signing any agreement.
chevron_right Learn more about loan amortization on Wikipedia
lightbulb Example Loan Scenario
Suppose you borrow $25,000 for a personal loan at 9% APR over a 5-year term. Your monthly payment would be approximately $519, and you would pay roughly $6,100 in total interest over the life of the loan.
If you shortened the term to 3 years, your monthly payment would rise to about $795 — but total interest paid would drop to around $3,600, saving you nearly $2,500.
Alternatively, if the lender offered a rate of 7% APR instead of 9% on the same 5-year term, your payment would fall to about $495/month and total interest to roughly $4,700 — a clear demonstration of how even 2 percentage points affects your total cost.
Many people use a loan calculator to compare lender offers, decide between loan terms, and understand the true cost of borrowing before submitting an application.
Loan Calculator FAQs
How is a loan monthly payment calculated?
Monthly payments are calculated using the standard amortization formula, which factors in the loan amount (principal), annual interest rate divided by 12 for the monthly rate, and the number of monthly payments. The formula ensures that each equal payment covers that month's interest charge plus a portion of the principal, so the balance reaches zero at the end of the term.
Is a longer loan term always better?
A longer term lowers your monthly payment, but you pay significantly more in total interest over the life of the loan. A shorter term costs more each month but saves money overall. The right choice depends on your cash flow needs — use the calculator to compare the total interest cost of different terms before deciding.
What happens if I make extra payments?
Extra payments go directly toward reducing your principal balance, which lowers the interest charged in all future months. Even one extra payment per year can meaningfully shorten the loan term and reduce total interest paid. For a detailed view of how extra payments work, see the amortization calculator.
What is the difference between APR and interest rate?
The interest rate is the cost of borrowing the principal expressed as a percentage. APR (Annual Percentage Rate) includes the interest rate plus most fees and costs associated with the loan, giving a more complete picture of the true annual cost. For comparing loans from different lenders, APR is the better number to use.
Loan calculator terminology
Loan Amount (Principal)
The total amount of money you are borrowing. Interest is charged on the outstanding principal balance each month, so a lower starting principal means less total interest paid.
Loan Term
The length of time over which you repay the loan, expressed in months or years. Longer terms lower monthly payments but increase total interest paid.
Annual Interest Rate (APR)
The yearly interest rate charged by the lender on the outstanding balance. Divided by 12 to get the monthly rate used in each payment calculation.
Monthly Payment
The fixed amount paid each month, covering both that month's interest charge and a portion of the principal. Stays constant for the full loan term on a fixed-rate loan.
Amortization
The process of gradually paying off a loan through scheduled installments. Early payments are weighted heavily toward interest; later payments shift toward principal as the balance declines.
Disclaimer: All calculators on this site are provided for informational and educational purposes only. Results are estimates based on the inputs you provide and mathematical formulas — they do not account for taxes, fees, inflation, risk, or other real-world factors that may affect financial outcomes. Past performance does not guarantee future results. Nothing on this site constitutes financial, investment, legal, or tax advice. Always consult a qualified professional before making financial decisions.
About FinanceCalcs.net — FinanceCalcs.net is a free financial calculator directory built and maintained by Ted Grajeda. The site exists to give everyone access to fast, accurate financial math — no subscriptions, no paywalls, no signup required. Every calculator runs entirely in your browser using standard financial formulas.