How this calculator works
The yearly summary keeps a long loan readable, while the monthly schedule shows the unrounded calculation behind every balance. Payment dates keep the selected day where possible and use month-end in shorter months. The final installment clears the remaining balance.
The formula
Interest this month = opening balance × annual rate / 1200. Principal paid = payment − interest. Closing balance = opening balance − principal paid.A quick example
A 12,000 loan at 0% over 12 months pays 1,000 each month. After the twelfth payment the balance is exactly zero.
How to use this calculator
- Choose the settings that match your scenario, using the units shown beside each field.
- Enter loan amount, annual nominal interest rate (%), term (whole months), first payment date.
- Calculate, then review the method and assumptions alongside the results.
A few common questions
Why do principal payments increase over time?
At a fixed payment, a declining balance attracts less interest, leaving more of the payment for principal.
Why can displayed rows differ by a cent when added?
Rows are calculated without intermediate currency rounding and then formatted to two decimals. The final balance is cleared explicitly.