Deposit Interest Calculator
Choose simple or compound interest and tax options to calculate your maturity amount.
Input Information
Result
Maturity Amount
10,296,100 KRW
Detailed Breakdown
| Principal | 10,000,000 KRW |
| Pre-Tax Interest | 350,000 KRW |
| Tax (15.4%) | - 53,900 KRW |
| After-Tax Interest | 296,100 KRW |
Deposit Interest Calculator: How to Make Your Sleeping Money Work
The foundation of financial management starts with "not losing money." In that sense, deposits are the most reliable and stable financial tool to safely protect and steadily grow your assets in a volatile investment market. In particular, term deposits that lock your money for a set period and receive promised interest are highly effective for achieving short-term financial goals like saving for a down payment on a house, paying a housing contract deposit, or funding a vacation.
However, even if you deposit the same amount, the final amount you receive at maturity can vary greatly depending on how interest is calculated (simple/compound) and whether taxes (taxable/non-taxable) apply. Many people sign up for deposits believing only the "3.5% annual rate" and are disappointed when they see the actual amount received after taxes at maturity.
SeriesCalc's Deposit Interest Calculator was created to solve this inconvenience. Simply enter the deposit amount, period, and interest rate, and you can easily check the actual amount you'll receive at maturity, considering complex interest calculations and taxes.
- Simple vs compound interest: which method is more favorable for you?
- How much tax will be deducted from your precious interest? (Based on 2025)
- How much more can you receive with non-taxable or tax-advantaged benefits?
- What's the difference in actual amount received between a 1-year and 2-year deposit?
Now, plan your future with accurate numbers instead of vague expectations. With SeriesCalc, the first step toward stable asset growth becomes easier and clearer.
Term Glossary
- Simple Interest
- Interest is calculated only on the initially deposited principal, so the same amount of interest accrues each period.
- Compound Interest
- Earned interest is added to the principal and the sum becomes the new principal; assets grow exponentially over longer periods.
- Interest Income Tax
- Deposit interest is taxed at general (15.4%), tax-preferred (9.5%), or non-taxable (0%); the rate greatly changes the net amount received.
Simple vs Compound Interest: How Is Interest Calculated?
Deposit interest calculation methods are broadly divided into simple and compound interest. The method you choose can result in significant differences in your maturity amount, especially as the deposit period lengthens.
1. Simple Interest
Interest is calculated only on the initial principal. Even when interest is generated, it is not included in the principal, so the same amount of interest occurs each period.
2. Monthly Compound Interest
Generated interest is added to the principal, and the combined amount becomes the new principal for calculating the next period's interest. This creates a "snowball effect" where interest grows exponentially over time.
* Monthly Rate = Annual Rate / 12
Tax That Determines Your Final Amount (Based on 2025)
Deposit interest is classified as "interest income" and is subject to taxation. Therefore, the final amount is the pre-tax interest minus tax. Since the tax rate varies by tax option, it's important to know which rate applies to you.
- General Taxation (15.4%): The basic rate applied to most financial products. 15.4% of interest income is withheld as tax. (Income tax 14% + Local income tax 1.4%)
- Tax-Advantaged (9.5%): Members or associate members of mutual financial institutions (NACF, Suhyup, credit unions, Saemaul Geumgo, etc.) can receive a lower tax rate on deposits up to 30 million KRW per person.
- Non-Taxable (0%): "Non-taxable comprehensive savings" for seniors (65+), disabled persons, independence activists, etc. exempts interest income from tax on deposits up to 50 million KRW per person.
5 Tips to Get Every Last Penny of Interest
1. Compare Rates Online Instead of Visiting Banks
You no longer need to visit multiple banks to find higher rates. Through services like the Financial Supervisory Service's "Financial Products at a Glance," the Korea Federation of Banks consumer portal, and various fintech apps (Toss, Kakao Bank, Bank Salad, etc.), you can compare all banks' deposit rates in real time and easily find the best conditions. Even a 0.1% rate difference can make a big difference over the long term.
2. Use Special Deposit Alerts
Banks occasionally sell "special deposits" at much higher rates than base rates to attract new customers or secure liquidity. They're so popular that quotas are filled within hours of launch. Set up app push notifications for banks you're interested in or watch fintech communities to catch these opportunities.
3. Think Twice About Automatic Renewal
Auto-renewal at maturity is convenient, but the rate at renewal may be lower than current rates. When rates are rising, it's often better to switch to a higher-rate product (redeposit) rather than auto-renew. Mark the maturity date on your calendar!
4. Maximize Non-Taxable/Tax-Advantaged Benefits
Operating deposits through an ISA (Individual Integrated Asset Management Account) allows you to receive tax-free benefits on interest and dividend income up to 2 million KRW (4 million KRW for basic type) within the account. Additionally, if you're 65+ or a person with disabilities, be sure to use the "non-taxable comprehensive savings" limit (50 million KRW) to save on taxes.
5. Remember the Depositor Protection Act Limit (50 Million KRW)
As a precaution, it's safe to deposit up to 50 million KRW (principal + interest) at a single financial institution. The Depositor Protection Act protects up to 50 million KRW per person even if a financial company goes bankrupt, so it's wise to spread large sums across multiple banks. Savings banks may offer higher rates but have relatively lower stability, so this principle should be followed more strictly.