Understanding flat vs reducing rate calculator
A flat quote charges interest against the original principal throughout the term, even as installments repay it. A reducing-balance quote charges against outstanding principal. The same percentage therefore describes different costs; compare total payments and actual cash-flow-based APR before deciding which offer is cheaper.
Formula and calculation method
Flat total interest = principal × quoted annual rate × years. Reducing EMI applies the monthly annuity formula to the outstanding balance.
Compares the same numerical quote under different calculation methods; a flat rate is not equivalent to the same reducing-balance APR. Fees and cash-flow timing differences are excluded.
How to use flat vs reducing rate calculator
- Set Loan principal. The example below uses 100000.
- Set Quoted annual interest (%). The example below uses 10.
- Set Loan months. The example below uses 24.
- Select Calculate to update the result. Reset restores the illustrated inputs. Copy, print or download your own result if you need a record.
Worked example
Example inputs
- Loan principal
- 100000
- Quoted annual interest (%)
- 10
- Loan months
- 24
- Flat monthly installment
- 5000
- Reducing monthly installment
- 4,614.49263375
- Flat total interest
- 20000
- Reducing total interest
- 10,747.82321004
- Extra interest under flat quote
- 9,252.17678996
Factors affecting your result
Compares the same numerical quote under different calculation methods; a flat rate is not equivalent to the same reducing-balance APR. Fees and cash-flow timing differences are excluded.
Changing loan principal changes the scenario being evaluated. Adjust one input at a time when comparing results, keep a copy of the assumptions, and compare values using the same unit and period. A precise arithmetic result does not make an uncertain assumption precise.
Frequently asked questions
How does the flat vs reducing rate calculator work?
Flat total interest = principal × quoted annual rate × years. Reducing EMI applies the monthly annuity formula to the outstanding balance.
What inputs does Flat vs Reducing Rate Calculator need?
Enter loan principal, quoted annual interest (%), loan months. Read the unit labels; percentages are entered as ordinary percentages, not decimal fractions.
How should I interpret the flat vs reducing rate calculator result?
Compares the same numerical quote under different calculation methods; a flat rate is not equivalent to the same reducing-balance APR. Fees and cash-flow timing differences are excluded.
Are my flat vs reducing rate calculator inputs uploaded?
No. The calculation runs in this browser. Favorites, recent tool names, theme and formatting preferences may be saved locally, but calculation inputs are not sent to a calculation server or stored by this website. Shared links do not include entered values.
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