Loan Installment Calculator
Estimate simple interest, compound growth, loan installments, total interest, and an amortization schedule.
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Interest and installment inputs
Simple interest uses annual nominal rate × duration. It does not compound.
Amortization schedule
The final payment is adjusted to close the remaining balance.
| Period | Starting balance | Payment | Interest | Principal | Ending balance |
|---|
Formulas and assumptions
Simple interest: P × (r / 100) × t. Compound interest: P × (1 + r / n)^(n × t). Loan installment uses the annuity formula A = P × i / (1 − (1 + i)^−N) with i = annual rate / 12.
The monthly rate is the annual nominal rate divided by 12. Actual lenders may use different day-count conventions, administration fees, insurance, or effective-rate methods. The result is an estimate, not an official quotation.
Frequently asked questions
What happens at zero interest?
The installment becomes principal divided by the number of months, and the amortization schedule has no interest component.
Are fees added to the financed principal?
No. Fees are displayed separately and added to total outlay. They do not change the installment formula.
Why does the final amortization payment differ?
Rounding can leave a few units of balance. The final payment is adjusted to settle the remaining principal exactly.