Loan payment calculator guide
A loan payment depends on the amount financed, note rate and repayment term. Fees can reduce the cash received or increase the financed principal, so payment alone does not show the complete borrowing cost.
Use written offer terms when available and compare APR, amount financed, finance charge and total of payments.
How to use this loan calculator
- Enter the amount: Use the requested principal before fees.
- Enter rate and term: Use the contractual note rate and number of monthly payments.
- Add origination fees: Specify whether the fee is deducted from proceeds or financed.
- Test extra principal: Enter an amount applied beyond the required payment.
- Compare disclosures: Review APR and total cost, not only payment.
Formula and variables
The fixed-payment formula amortizes principal and interest over equal monthly periods.
M = P × [r(1+r)^n] ÷ [(1+r)^n − 1]- P — Principal financed
- Loan amount plus any financed fee. (USD)
- r — Monthly rate
- Annual note rate divided by 12.
- n — Payments
- Repayment term. (months)
Worked example: $15,000 loan at 8% for 36 months
Assume no origination fee or extra payment.
- Principal
- $15,000
- Rate
- 8%
- Term
- 36 months
- Convert 8% to a monthly rate.
- Apply the fixed amortization formula for 36 payments.
Result: Approximately $470 per month
Fees would increase cost and may change cash received or principal financed.
Understanding your results
Scheduled payment
Required principal and interest under the entered fixed terms.
Total interest
Interest across the modeled payoff path.
Cash received
Requested amount minus a fee deducted upfront; financed fees instead increase principal.
Assumptions
- Fixed rate and monthly payments.
- Extra amounts reduce principal.
- No late fees, payment holidays or penalties.
Limitations
- APR is not derived from every possible disclosure rule.
- Variable, interest-only and balloon loans require different models.
- Lender rounding can differ.
Common mistakes
- Comparing payment without APR or fees.
- Extending the term without checking total interest.
- Confusing requested amount with cash received.
- Failing to confirm how extra payments are applied.
Practical use cases
Compare installment offers
Use identical amount and term assumptions.
Plan faster payoff
Estimate time and interest saved from extra principal.
Planning and decision guide
APR and note rate are not interchangeable
The note rate drives scheduled interest; APR is a standardized cost measure that can incorporate certain fees. Compare both.
Negotiate total cost, not only payment
A lower payment created by a longer term may cost more overall. Review amount financed, finance charge and total of payments.
Frequently asked questions
How is a loan payment calculated?
A fixed payment amortizes principal and interest across the selected number of months.
Does this calculator include origination fees?
Yes. Model a fee deducted from proceeds or added to principal.
Do extra payments reduce interest?
When applied to principal, they generally reduce the balance used for later interest.
Why does my lender payment differ?
The contract may use different timing, fees, rounding or loan features.
Sources and review
- What is a personal installment loan? — Consumer Financial Protection Bureau. Accessed 2026-07-10.
Reviewed 2026-07-10.