Fixed Deposit vs Installment Savings vs Parking Account Calculator (after-tax interest)

How it works

Total = monthly amount × months. Installment savings (적금) pay simple interest on each deposit only for the months it is held: interest = monthly amount × rate ÷ 12 × n(n + 1) ÷ 2, so the money earns on average only about half the stated rate. A fixed deposit (예금) of the whole total earns total × rate × months ÷ 12. The parking account compounds monthly at rate ÷ 12, with tax taken from each payment. “Installment + parking” keeps the total in a parking account and moves one monthly amount into the installment account at the start of each month; the waiting balance earns simple monthly interest. Tax = interest × the tax rate. Products that count days, or pay bonus rates, will differ slightly.

⚠ Estimates for information only — not financial advice.

FAQ

Why does a 4% installment account pay less than a 3% deposit?

Because only the first deposit earns interest for the full year; the last one earns for a single month. On average your money is in the account for about half the term, so the effective rate is roughly half the stated one.

Which one should I pick?

If you are saving from your monthly pay, an installment account builds the habit. If you already have the full sum, compare the deposit with “installment + parking” — the higher number wins. Check deposit protection limits and early-withdrawal terms.

Checked 11 Nov 2026. Simple-interest formula for fixed monthly installment savings (정액적립식 적금) and fixed deposits; Korean tax on interest: 14% income tax (Income Tax Act art. 129) plus local income tax of 10% of it (1.4%), total 15.4% — editable.