Loan Calculator with Interest
Calculate monthly payment, total interest, and total cost for any loan — personal, student, business, RV, or anything else with a fixed rate and term.
What is Loan Calculator with Interest?
The loan calculator handles any loan with a fixed rate and term — personal loans, student loans, business loans, RV/boat loans, debt consolidation. Enter the principal, APR, and term in months; get the monthly payment, total interest, and total cost.
If the loan has an origination fee, the calculator computes the effective APR — what the loan actually costs you, accounting for the fee deducted upfront.
Formula
Standard amortization: M = P × r × (1+r)N ÷ ((1+r)N − 1), where M is monthly payment, P is principal, r is monthly rate (APR/12/100), and N is number of months.
Effective APR with origination fees: solve for the rate at which the present value of the monthly payments equals the net principal (loan amount minus fee). Found numerically via bisection.
Worked example
$20,000 loan at 9.5% APR over 60 months, $200 origination fee:
- Monthly payment: $419.71
- Total interest over 5 years: $5,182.49
- Total cost: $25,382.49
- Effective APR (with fee): 9.85%
How to use this calculator
- Enter the loan amount, rate (APR), and term in months.
- Add the origination fee if any (typically 1-8% of principal for personal loans).
- The calculator returns monthly payment, total interest, total cost, and effective APR.
Frequently asked questions
What's a typical interest rate for a personal loan?
2025 personal loan APRs range from about 6% (excellent credit, secured) to 35%+ (subprime). Average for prime borrowers (700+ credit score) is 9-13%. Subprime is often 20-30%.
What's the difference between APR and interest rate?
The interest rate is what you pay on the principal annually. APR includes the interest rate PLUS fees (origination, processing, etc.) annualized. APR is a more honest cost number for comparing loans because it captures the true total cost.
Should I take a longer term to lower monthly payments?
It lowers the payment but you pay more total interest. A $20K loan at 10% over 36 months: $645/mo, $3,236 interest. Same loan over 60 months: $425/mo, $5,498 interest. The longer term costs $2,262 more even though the monthly is $220 lower.
What's an origination fee?
A one-time fee charged at loan origination, deducted from the disbursed amount. For a $20K loan with $200 fee, you receive $19,800 but owe $20K. Personal loans commonly have 1-6% origination fees; some lenders charge zero.
Can I prepay without penalty?
Most modern personal and student loans have no prepayment penalty. Always confirm in writing before signing. Some older mortgages and subprime loans do have penalties, especially in the first 1-3 years.