Korea Savings & Deposit Interest Calculator
Enter the principal for a lump-sum deposit (예금) or the monthly contribution for installment savings (적금), plus the annual rate and term, to calculate pre-tax and after-tax interest — including the 15.4% interest income tax withholding — and your maturity payout.
Legal Basis
- Basis: Income Tax Act, Article 129(1)(1)(d) (14% withholding rate on general interest income) — View full statute
- Basis: Local Tax Act, Article 103-13(1) (individual local income tax special withholding, 10% of the withheld income tax) — View full statute
Frequently Asked Questions
Why is interest calculated differently for lump-sum deposits vs. installment savings?
A lump-sum deposit (예금) sits at the bank in full from day one to maturity, but with installment savings (적금) you contribute month by month, so each contribution earns interest for a different length of time. The 1st contribution earns interest for the entire term, while the last contribution earns only 1 month's worth.
Why is the actual interest on my "4% APY" installment account so much lower?
This is the sticker-rate illusion. Over a 12-month term, your money is on deposit for roughly half the term on average, so the actual interest ends up around half of "monthly contribution × 12 × rate." Check the per-installment breakdown table in this calculator's results to see exactly how many months each contribution earns interest for.
Is interest income tax always 15.4%?
For ordinary deposits and installment savings, yes (14% income tax + 1.4 percentage points local income tax). Tax-advantaged products — such as tax-free comprehensive savings for seniors/people with disabilities, or preferential-rate savings at credit unions — are outside this calculator's scope and may have a different effective rate.
What's the difference between simple and compound interest, and which does this calculator use?
Simple interest accrues only on the principal; compound interest also accrues on interest already earned. This calculator's compound option is fixed at monthly compounding — if your actual product compounds quarterly or annually, your real result may differ slightly.
Does this calculation change if I withdraw early?
Yes. Withdrawing before maturity almost always triggers a much lower early-withdrawal rate than the advertised rate. This calculator only computes interest for holding the product to maturity as agreed — check your specific product's early-withdrawal rate separately if that's a possibility.