How to use this calculator
- Enter loan principal, flat annual rate (%), monthly installments.
- Choose a display currency, then select Calculate. Results also update after a brief pause while you edit.
- Read the result with the assumptions below. Export details or save a second scenario to compare your choices.
Formula and method
Assumptions and limitations
This computes a flat contract scenario only. Fee-inclusive effective cost is a separate cash-flow calculation.
Worked example
With loan principal = 10000, flat annual rate (%) = 6, monthly installments = 24, total flat interest is approximately 1200.
What the result means
The same numerical flat and reducing-balance rates do not imply the same borrowing cost.
Common questions
How should I interpret total flat interest?
The same numerical flat and reducing-balance rates do not imply the same borrowing cost.
What should I check before using this result?
This computes a flat contract scenario only. Fee-inclusive effective cost is a separate cash-flow calculation.
Methodology and transparency
Calculation specification reviewed on 2026-10-14. Mathematical implementation is tested against independent reference fixtures. This does not imply review by a licensed financial professional. Read the testing and precision policy.