A walkthrough, end to end.
- 1
Enter the loan amount, interest rate (APR) and term.
- 2
The calculator solves the standard amortization formula for the level monthly payment.
- 3
Read total interest paid, total cost of the loan, and your interest-vs-principal split for the first few years.
Loan amortization (PMT)
Same formula every lender uses. The level monthly payment is set so the loan amortizes (pays off completely) by the end of the term. Interest accrues on the outstanding balance each month; the rest of the payment reduces principal.
What you can do with this.
Personal loan calculator
Unsecured personal loans typically run 5–15% APR with 2–7 year terms. Use the calculator to compare quotes from different lenders — even a 1% APR difference materially changes total cost.
Student loan calculator
Federal student loan rates are set yearly by Congress; private loans vary. Standard repayment is 10 years; income-driven plans can stretch to 20–25 years and reduce monthly payment but add total interest.
Business loan calculator
SBA loans run 5–11% APR over 7–25 years; bank-direct business loans are similar. The calculator helps validate the lender's quoted payment matches the math.
Compare two loan offers
Run the calculator twice with each lender's APR and term, then compare total interest. The lower-payment option usually has a longer term — sometimes that's right, sometimes a shorter higher-payment loan saves significantly.
Loan with extra principal
Even a small extra payment each month accelerates payoff disproportionately because every extra dollar of principal saves interest on the remaining balance for the full term.
Affordability check
Lenders generally cap total debt service (DTI) at 40–43% of gross monthly income. Sum your existing debt + the calculated payment and divide by gross monthly to see if you're within range.
APR vs. interest rate
APR includes origination fees and other costs; the interest rate alone doesn't. Always compare loans on APR, not just rate. The calculator uses APR as the rate input.
Loan calculator 2026 — what's current
Online lenders (SoFi, LightStream, Marcus) routinely beat traditional bank rates for prime borrowers. Check 3+ quotes; rates can spread by 5%+ for the same borrower.
Frequently asked.
Highly credit-dependent. Prime borrowers (FICO 720+) often see 7–10%; near-prime 12–18%; subprime 20–30%+. Compare your quote to averages on Bankrate or LendingTree.
Lower monthly payment, much higher total interest. Only stretch the term if affordability is the binding constraint. Otherwise the shortest term you can comfortably afford saves the most.
Almost always — every extra dollar reduces principal and saves interest at your loan's rate. Make sure your loan has no prepayment penalty (most modern personal loans don't).
Most US installment loans use simple monthly interest calculation, which is what this calculator assumes. Some loans use daily simple interest (slightly different); confirm with your lender.
No. Calculations run entirely in your browser. Nothing is sent to a server.