Instalment Calculator
Compare monthly payments and total interest for 0% and amortising instalments.
Add a down payment · optional
Interest-bearing mode assumes level monthly amortising payments. Card-specific daily fees and partial-interest promotions are not included.
Formulas & edge cases tested · 2026-10-20 · Calculation basis
Formulas, assumptions and checks
Amount financed = price − down payment. Interest-free payments = amount financed ÷ months. Amortising payments = P×r÷[1−(1+r)⁻ⁿ], where r is the annual rate divided by 12 and 100. Figures are rounded for display; lender-specific fees, day counts and final-payment adjustments are excluded.
Checked: zero interest, full down payment, comma-separated amounts, valid whole-month terms, very small rates and term comparisons.
CFPB · Amortisation ↗신한카드 · 할부 수수료 계산 방식 ↗How to use Instalment Calculator
Split the amount financed equally for 0% instalments, or use level monthly amortising payments for an interest-bearing plan. Compare terms at the same price, down payment and rate. Card-specific daily fees and partial-interest promotions are excluded.
Displayed values follow the definitions stated above.
How the down payment and term affect total cost
Interest applies to the purchase price after subtracting the down payment. Compare several down payments and terms to see the trade-off between the monthly payment and total financing cost.
The monthly payment applies the amortising payment formula to the amount financed.
Recommended steps
- Use the actual financed price if it differs from the cash price.
- Enter the amount paid upfront as the down payment.
- For a 0% offer, enter a zero rate and check for separate fees.
How to interpret the result
- A larger down payment reduces both the financed amount and total interest.
- A longer term lowers the monthly payment but can increase total cost.
- Processing fees, balloon payments and residual values may be separate.
Frequently asked questions
How do I calculate a 0% instalment plan?
Enter an annual rate of 0%. The amount financed will be divided by the number of months.
Can the down payment exceed the price?
No. It must be no greater than the purchase price; an equal amount leaves nothing to finance.
Can I use this for car finance?
It is useful for a simple amortising comparison, but taxes, fees, residual values and contract terms must be added separately.