Loan calculators: understand payments, interest and payoff time
Plan a personal, auto, installment or other fixed-rate loan with transparent assumptions. Enter your own rate and terms; these tools do not quote lenders or use live market rates.
1. Monthly payment & total interest
For fixed-rate loans with equal monthly payments. APR may differ from the stated interest rate when fees are included.
First 12 payments
| Month | Payment | Interest | Principal | Balance |
|---|
2. Extra payment payoff planner
Estimate how an additional monthly principal payment could reduce interest and shorten payoff. Assumes no prepayment penalty and that extra amounts go directly to principal.
3. Side-by-side loan offers
Compare two hypothetical loans with the same borrowed amount. This compares principal and interest only; use the fee tool below for additional costs.
4. Fees & estimated total borrowing cost
Add an upfront origination or processing fee to the total scheduled payments. A fee-adjusted effective annual rate is not calculated here; a lender’s disclosed APR may include fees under applicable rules.
5. Payment-based loan amount
Estimate how much principal fits a monthly payment budget at your selected interest rate and term. Taxes, insurance, fees and other debt obligations are excluded.
6. Debt-to-income ratio (DTI)
DTI is monthly debt payments divided by gross monthly income. Lenders may define eligible income and debts differently.
What these numbers mean
Monthly payment is the amount due under an equal-payment schedule. Principal is the amount borrowed; interest is the borrowing charge. Total interest is scheduled payments minus principal, before separate fees. A longer term can lower the payment while increasing total interest.
The chart separates principal and interest for the first calculation. The amortization table shows how early payments generally include more interest when the remaining balance is higher.
Make a better borrowing decision
Start with the full cost, not just the advertised payment. For instance, stretching a loan from four years to six may make the monthly amount easier to manage, but it can increase the dollars spent on interest. An origination fee may reduce the funds you actually receive while leaving the repayment obligation unchanged.
Use the worked examples to compare offers, the borrowing guide for important contract terms, and the methodology to audit each formula. These are independent educational tools, not lender recommendations.