Loan Calculator - Monthly Payment, Amortization Formula & Schedule
A loan calculator uses the fixed-payment amortization formula to estimate your monthly installment from loan amount, APR, and term. A $20,000 personal loan at 8% APR for 60 months costs about $406 per month and $24,332 total - including roughly $4,332 in interest. Enter your numbers to see the payment schedule and compare how term length changes total borrowing cost.
Loan Details
Enter your loan parameters below.
Payment Summary
Estimated monthly payment and total cost.
Monthly payment
$500.95
Over 60 months
Methodology and limitations
Last reviewed:
Methodology
Uses the fixed-payment installment loan formula with loan amount, APR, term in months, and loan type to estimate payment and interest.
Limitations
Does not include origination fees, taxes, insurance, variable-rate changes, prepayment penalties, or lender-specific payment rules.
Official sources
How to Use the Loan Calculator - Monthly Payment, Amortization Formula & Schedule
A loan calculator uses the fixed-payment amortization formula to estimate your monthly installment from loan amount, APR, and term. A $20,000 personal loan at 8% APR for 60 months costs about $406 per month and $24,332 total - including roughly $4,332 in interest. Enter your numbers to see the payment schedule and compare how term length changes total borrowing cost.
Method used
This calculator uses the standard fixed-payment loan formula. It converts APR to a monthly rate, calculates the level monthly payment, and estimates how much total interest accumulates across the term.
Practical example
Example: a $25,000 loan at 7.5% for 60 months produces a monthly payment estimate and a schedule showing how each payment is split between interest and principal.
What this includes
- Includes principal-and-interest payments for fixed-rate installment loans.
- Works for planning personal, auto, student, and other monthly loans.
What this excludes
- Does not include lender fees, taxes, insurance, or variable-rate changes.
Frequently Asked Questions
How is the monthly loan payment calculated?
The calculator uses the standard fixed-payment amortization formula for installment loans. It converts your annual percentage rate (APR) to a monthly rate by dividing by 12, then spreads the loan balance evenly across the selected number of monthly payments. The result is a level payment where early installments are mostly interest and later ones apply more to principal. Enter loan amount, APR, and term to see the monthly payment, total interest, and full schedule.
What loan types can I use this for?
Use this calculator for fixed-rate personal loans, auto loans, student loans, home equity installment loans, and other term loans with regular monthly payments. It works best when the interest rate and payment amount stay constant throughout the loan. It is not designed for variable-rate credit lines, interest-only loans, revolving credit cards, or loans with balloon payments at the end of the term.
Does the loan calculator include fees?
No. The calculation focuses on principal and interest only. Origination fees, application fees, prepayment penalties, taxes, insurance, and other lender charges are not included in the monthly payment estimate. When comparing real loan offers, add those costs separately or ask the lender for the APR, which reflects some fees. A lower stated rate with high fees may cost more than a slightly higher rate with no fees.
Why does a longer loan term cost more?
A longer term spreads the same principal across more months, which lowers your monthly payment and can improve cash flow. However, interest accrues on the outstanding balance every month, so more months means more total interest paid over the life of the loan. For example, a $20,000 loan at 8% costs about $4,332 in interest over 5 years but roughly $7,372 over 10 years - nearly double - even though the monthly payment is lower.
How much interest will I pay on my loan?
Total interest depends on three factors: the loan amount, the annual interest rate, and the repayment term. This calculator shows total interest paid alongside the monthly payment and full amortization schedule. To reduce interest, choose a shorter term, make extra principal payments, or secure a lower APR before signing. Comparing total interest across different term lengths helps you balance affordable monthly payments against long-term borrowing cost.