Loan Calculator: quick answer
Estimate monthly payments, total interest, payoff time, and amortization for standard installment loans.
Loan amount, Interest rate, and Loan term.
Monthly payment, Total interest, Total borrowing cost, and Payoff time.
Build a realistic base case, then change one assumption at a time and compare the chart and table, not only the first result.
What this calculator does
This loan calculator estimates how a standard amortizing loan behaves from the first payment to the last. It is designed for personal loans, unsecured installment loans, small business borrowing, and any other credit product where the balance declines over a fixed repayment term.
A useful payment estimate does more than show one monthly number. It should also reveal how much interest you will pay in total, how quickly the balance falls, and whether small extra payments materially reduce the payoff period.
Borrowers can use this page as a screening tool before comparing lender quotes. It helps test whether a lower rate, shorter term, or consistent overpayment produces a better overall borrowing outcome.
This page is built for users who need a defensible planning answer, not just quick arithmetic. It translates "Loan amount", "Interest rate", and "Loan term" into "Monthly payment", "Total interest", and "Total borrowing cost" so the trade-off is visible in one place instead of being hidden behind a single number. It is also useful for comparing closely related searches such as "personal loan calculator", "installment loan calculator", and "loan payment calculator", as long as the assumptions match the product or decision you are actually evaluating.
How to use the loan calculator
- Enter the amount you want to borrow, the quoted annual interest rate, and the repayment term in years.
- Open Advanced options if you want to include an origination fee or a recurring extra principal payment.
- Review the summary cards first, then scan the amortization table to understand how the interest share changes over time.
- Start with "Loan amount", "Interest rate", and "Loan term", then check whether the first output cards already answer your question. After that, add advanced assumptions such as "Extra monthly payment" and "Origination fee" only when they are real enough to change the decision.
Formula and methodology
The calculator assumes a fully amortizing loan with equal monthly installments unless the balance reaches zero early because of extra payments.
Interest is calculated using a nominal annual rate divided into monthly periods. Extra payments are applied directly to principal after interest for that month is covered.
The output is an estimate only. Lenders may use different fee structures, payment frequencies, rounding rules, or disbursement dates.
The model maps "Loan amount", "Interest rate", and "Loan term" into "Monthly payment", "Total interest", and "Total borrowing cost" using the formulas shown on the page. Keeping those relationships visible makes it easier to separate the core economics from the optional adjustments and to understand which assumption is actually moving the answer.
Formula
Here, P is the principal, r is the monthly interest rate, and n is the total number of monthly payments.
When the interest rate is zero, the payment simplifies to principal divided by the number of periods.
Worked example and practical context
A 25,000 loan at 8.5% over 5 years produces a fixed monthly payment. If you add an extra 75 each month, principal falls faster and the total interest bill declines.
The most useful comparison is not just the lower monthly payment from a longer term, but the trade-off between affordability now and interest cost over the life of the loan.
How to interpret the results
Monthly payment tells you the cash-flow commitment. Total interest tells you the price of time. Payoff months show whether your extra payments are materially changing the timeline.
If a lender offers a slightly lower rate but adds a higher fee, compare the total borrowing cost rather than the headline payment alone.
Read "Monthly payment" first, then use the other summary cards, the chart, and the detailed table to judge short-term affordability and long-term borrowing cost. In most finance decisions, the best option is the one that stays strong across the full picture, not just the one with the most attractive first number.
Common mistakes to avoid
- Comparing loans only by monthly payment and ignoring total interest paid.
- Using the promotional rate instead of the actual annual rate after introductory periods or fees.
- Forgetting to model extra payments consistently when planning an aggressive payoff strategy.
Key terms
- Amortization
- The gradual repayment of a loan through scheduled payments that cover both interest and principal.
- Extra payment
- Any amount paid above the scheduled installment, usually applied to principal to shorten the loan life.
Frequently asked questions
Practical answers about assumptions, results, and responsible use.