Savings Calculator
Also works as a deposit interest calculator. Enter the amount, rate and term to see the after-tax maturity amount after deducting 15.4% interest income tax. Simple interest, monthly compound interest and tax-exempt savings are all supported.
Enter Savings Details
Enter the pre-tax contractual rate. Only 0–20% is calculated.
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Estimated Maturity Amount
2026-01 rates applied, 15.4% interest tax · Basis- Total Principal
- 10,000,000KRW
- Pre-tax Interest
- 350,000KRW
- Interest Income Tax 14%
- −49,000KRW
- Local Income Tax 1.4%
- −4,900KRW
- After-tax Interest
- 296,100KRW
- Maturity Amount
- 10,296,100KRW
Interest income tax is 14% income tax + 1.4% local tax = 15.4%. Tax amounts are truncated below KRW 10, so the bank's actual payout may differ by a few KRW.
Installment savings earn less interest than deposits because each monthly deposit only accrues interest from its payment date to maturity.
Tax-free comprehensive savings (비과세종합저축) covers principal up to KRW 50 million. From Jan 1 2026, only basic pension recipients can newly enroll. Interest on principal exceeding the cap is taxed normally.
Promotional rates, early withdrawal rates, and tax-advantaged accounts (ISA) are not reflected.
머니플(Moneyple)의 적금·예금 계산기는 단리·월복리 방식의 만기 세후 수령액을 계산한다. 이자소득세 15.4%와 비과세종합저축을 선택할 수 있다.
What This Number Means
매월 50만원씩 12개월, 연 3.5% 적금이면 만기 시 원금 600만원에 이자가 붙고 이자소득세 15.4%를 뗀 세후 수령액을 알 수 있다.
3 Common Mistakes People Make Here
- 적금 금리와 예금 금리의 이자 계산 방식이 같다고 생각한다 — 적금은 매월 불입하므로 전체 원금에 금리가 적용되지 않는다.
- 세전 이자를 실수령 이자로 착각한다 — 이자소득세 15.4%가 원천징수된다.
- 월복리가 무조건 유리하다고 생각한다 — 단기에는 차이가 미미하고 금리가 높을수록 차이가 커진다.
적금 이자에는 이자소득세 15.4%(소득세 14% + 지방소득세 1.4%)가 원천징수된다 — 비과세종합저축은 이 세금이 면제된다.
머니플(Moneyple) · Formulas and rates verified by humans; commentary drafted with AI assistance and reviewed by the operator
How is savings interest calculated?
Installment savings (jeokgeum, 적금) works on the principle that each monthly deposit earns interest only for its remaining term. In a 12-month plan, the first deposit earns 12 months of interest, the second earns 11 months, and the last earns only 1 month. So the interest on a 12-month plan equals roughly "monthly deposit × annual rate × 6.5" (the sum 1+2+…+12 = 78 months divided by 12). Fixed deposits (yegeum, 예금) are the opposite: the full lump sum earns interest from day one to maturity.
Fixed deposit (simple) — Gross interest = principal × annual rate × (months ÷ 12)
Installment savings (simple) — Gross interest = monthly deposit × annual rate × n(n+1) ÷ 24
Monthly compound — Maturity = principal × (1 + annual rate÷12)^months
After-tax interest = gross interest − income tax (14%) − local income tax (10% of income tax)
Example: A 10-million-KRW fixed deposit at 3.5% for 12 months yields gross interest of 350,000 KRW. After deducting income tax of 49,000 KRW and local tax of 4,900 KRW, net interest is 296,100 KRW for a maturity amount of 10,296,100 KRW. If you instead contribute 500,000 KRW/month at 4.0% in installment savings for the same period, total deposits are 6,000,000 KRW with gross interest of only 130,000 KRW and net interest of 109,980 KRW, giving a maturity of 6,109,980 KRW. Even though the savings rate is 0.5%p higher, interest is lower because deposits are spread over time.
Note: The starting point is the bank's advertised pre-tax contractual rate. If preferential-rate conditions (payroll transfer, card spending, auto-transfer, etc.) are not met, only the base rate applies. Early termination uses a much lower penalty rate instead of the contractual rate. This calculator does not evaluate those conditions, so actual proceeds may differ depending on the product terms.
How much tax is deducted from interest?
Savings interest is taxed at 15.4%, combining 14% income tax (Income Tax Act Art. 129) and 1.4% local income tax (10% of the income tax, Local Tax Act Art. 92). The bank withholds it at maturity, so you do not need to file separately.
- Separate taxation (bunri-gwase, 분리과세) — If total annual interest and dividends are 20 million KRW or less, the 15.4% is the final tax.
- Comprehensive financial income tax (jonghap-gwase, 종합과세) — Amounts exceeding 20 million KRW are aggregated with other income and taxed at progressive rates. This calculator cannot know your other financial income, so it only shows a warning.
- Tax-exempt comprehensive savings (bigwase jonghap jeochuk, 비과세종합저축) — Up to 50 million KRW in principal is completely tax-free (Restriction of Special Taxation Act Art. 88-2). Eligibility was narrowed for accounts opened from January 1, 2026.
- Truncation rules — This calculator truncates gross interest to the nearest KRW and tax amounts to the nearest 10 KRW. The bank's actual payment may differ by a few KRW.
The reduced tax (1.4% agricultural surtax) on mutual-finance deposits (Saemaul Geumgo, credit unions, agricultural cooperative unit associations, etc.) is transitioning to separate taxation based on associate-member income criteria from 2026, making the conditions complex. This calculator does not include it. If you use such products, check with the cooperative directly.
Frequently Asked Questions
Q. Why is installment savings interest lower than deposit interest?
Because the money stays in the bank for different durations. A fixed deposit earns interest on the full lump sum from day one to maturity. Installment savings deposits are made monthly, so only the first installment earns 12 months of interest while the last earns just 1 month. The average holding period for a 12-month plan is about 6.5 months, so even at the same rate and total amount, interest is roughly half that of a deposit. That is why installment savings rates are typically displayed higher than deposit rates.
Q. How is the 15.4% interest income tax calculated?
The 14% income tax (Income Tax Act Art. 129) plus 1.4% local income tax (10% of the income tax, Local Tax Act Art. 92) equals 15.4%. The two taxes are computed and withheld separately. This calculator truncates tax amounts below 10 KRW (in the spirit of National Treasury Act Art. 47). Banks follow the same method but may truncate at a different stage, causing a few KRW difference from the actual payment. If annual financial income does not exceed 20 million KRW, this 15.4% is the final tax (separate taxation).
Q. Who is eligible for tax-exempt comprehensive savings?
This is a program under the Restriction of Special Taxation Act Art. 88-2 where interest and dividend income on up to 50 million KRW in principal is tax-free. From January 1, 2026, eligibility for new accounts was narrowed to basic pension recipients and similar groups (previously ages 65+). People with disabilities, independence merit holders and basic livelihood recipients remain eligible as before. Accounts opened by December 31, 2025 retain the benefit until maturity. The sunset date is December 31, 2028.
Q. How much difference does simple vs. monthly compound interest make?
Less than you might expect for short terms, but it grows with time. A 10-million-KRW deposit at 3.0% for 12 months earns 300,000 KRW in simple interest vs. 304,159 KRW with monthly compounding — a difference of about 4,159 KRW. Compounding means interest earns interest, so the gap widens with longer terms; at 3–5 years, it becomes meaningful. Most fixed deposits use simple interest; monthly compounding is available only on select products.
This calculator is for reference only. Actual amounts may differ due to product terms, preferential-rate conditions, early-termination rates and regulatory changes, and the results have no legal effect. Confirm the exact maturity payout with your financial institution.