Installment vs. one-time payment comparison calculator
Compare the expected total amount and monthly payment range with the payment amount, installment months, annual fee rate, and one-time payment discount rate.
Input
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Result
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A comparison example: apply a simple monthly rate divided by 12 to the remaining principal based on the monthly fee rate entered by the user. Divide the principal evenly and round the monthly fee to the nearest whole unit. The principal distribution, usage days, billing dates, and zero-interest terms may vary by card issuer. Check the actual applied rate and amount in the card issuer app and usage invoice for details. This is not product recommendation or actual amount calculation.
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Calculation·conversion criteria
Compare the payment amount with the one-time payment discount and the installment fee conditions entered by the user to confirm the expected fee, monthly payment range, and total amount.
Input example
Payment: 1,000,000 won · 6 months · annual fee rate 15% · one-time payment discount rate 0.5% → installment fee 43,750 won · total installment amount 1,043,750 won · one-time payment 995,000 won
If the purchase price is 1,000,000 won, the term is 6 months, the annual fee rate is 15%, and the lump-sum discount is 0.5%, the principal is split into installments of 166,666–166,667 won. Applying the monthly rate (annual rate ÷ 12) to the remaining principal gives a rounded installment fee of 43,750 won and an estimated installment total of 1,043,750 won. After the lump-sum discount, the price is 995,000 won, a difference of 48,750 won. The estimated first-month payment is 179,167 won, and the last-month payment is 168,749 won.
How to use
- Use the provided example value or replace the payment amount (won), installment months, annual installment rate (%), and one-time payment discount rate (%) fields.
- Click Verify result and check the following result.
- Result can be copied if needed.
Frequently Asked Questions
How is the installment fee calculated?
Multiply the monthly rate divided by 12 by the remaining principal at the start of each cycle. Divide the principal equally and distribute the remainder to the previous cycle. Round the fee amount to the nearest whole unit.
Why is the card description amount different?
Actual fee rate, usage days, payment date, principal distribution, zero-interest offer, and card company billing rules may vary. Actual conditions can be checked in the card company app or billing statement.
Can we also compare interest-free installment or one-time payment options?
Enter 0 for the annual interest rate, and enter the one-time discount rate for the one-time payment discount. Points, cashback, financing offers, and opportunity costs are not calculated automatically.
Calculation criteria and reference materials
- Yoon Shin Financial Association Consumer Support Center — Credit Card Usage Guide
Guides the path to check the card installment fee and actual application rate. The calculator uses only the installment fee rate entered by the user and does not look up the card issuer rate.
- Yoon Shin Financial Association — Credit Card Product Disclosure
It links to the public information of the card product’s interest rate and fee rate. It does not automatically input the latest installment terms of a specific card into this calculator.
Verification of calculation criteria: · Calculation·verification principles · Report errors