Model interest accrued during a payment-free deferment followed by fixed monthly repayment.
The calculator keeps the balance, rate convention, payment timing, fees, and term visible so you can reproduce the result and compare it with an actual offer or statement.
The cash-flow relationship
Place every amount at the correct time
Repayment balance = (principal + financed fees)·(1 + nominal annual rate/12)^deferment months; that balance then amortizes over the repayment term.
Visual explanation
What changes the borrowing result
StartPhase 1Phase 2Final payment / balanceRepayment balance = (principal + financed fees)·(1 + nominal annual rate/12)^deferment months; that balance then amortizes over the repayment term.
Read the result in context
Use the estimate with its contract assumptions
At a zero rate, a 12,000 principal plus 300 financed fee remains 12,300 through deferment and repays as 1,025 over 12 months.
Interest compounds monthly and no payment is made during the entered deferment. Real contracts may subsidize interest, capitalize it on a different date, or treat fees differently.
Quick guide
How to use this calculator
Enter every amount in one consistent currency.
Use the nominal annual rate and whole-number monthly timing requested by each label.
Read the result together with the stated timing convention and calculator-specific exclusions.
Calculation method
Calculation method
Repayment balance = (principal + financed fees)·(1 + nominal annual rate/12)^deferment months; that balance then amortizes over the repayment term.
Entered monetary components are aggregated as exact fixed decimals. Amortization keeps full calculation precision and rounds only for presentation; a nonzero supported result is never displayed as zero.
Worked example
Worked example
At a zero rate, a 12,000 principal plus 300 financed fee remains 12,300 through deferment and repays as 1,025 over 12 months.
Repayment balance = (principal + financed fees)·(1 + nominal annual rate/12)^deferment months; that balance then amortizes over the repayment term.
Supported inputs
Precision and limits
Visible input limits
Amounts are capped at 1e12, nominal annual rates at 1000%, schedules at 1,200 months, and fixed-decimal inputs at 12 decimal places.
Estimate, not an offer
Results model only the entered values. A lender or contract may use different payment dates, day counts, compounding, fee treatment, statement rounding, or allocation rules.
International scope
No currency, country, tax, credit-scoring system, consumer-credit law, or lender policy is assumed. Location-dependent amounts must be entered explicitly.
Calculator-specific assumptions
Interest compounds monthly and no payment is made during the entered deferment. Real contracts may subsidize interest, capitalize it on a different date, or treat fees differently.
