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Deposit Interest Calculator

What could a lump-sum deposit
be worth at maturity?

Estimate the maturity value after interest and tax using a deposit amount, term, and annual rate.

Assumptions

Reset

Enter the nominal annual rate actually applied to the deposit.

Choose monthly compounding only when the product explicitly uses it.

The estimate assumes one lump-sum deposit held to maturity with interest paid at maturity.

DEPOSIT MATURITY SCENARIOS

Compare after-tax interest and maturity value
by deposit, rate, and term.

These examples assume 3.5% simple interest and the 15.4% standard Korean interest tax.

Principal, interest, tax, and maturity value are calculated estimates. Actual results can differ because of day-count conventions, rounding, and product terms.

By deposit amount

1 year · 3.5% annual rate · simple interest · 15.4% standard Korean interest tax

Principal
₩10,000,000
Pre-tax interest
₩350,000
Estimated tax
₩53,900
After-tax interest
₩296,100
Maturity value
₩10,296,100
Principal
₩30,000,000
Pre-tax interest
₩1,050,000
Estimated tax
₩161,700
After-tax interest
₩888,300
Maturity value
₩30,888,300
Principal
₩50,000,000
Pre-tax interest
₩1,750,000
Estimated tax
₩269,500
After-tax interest
₩1,480,500
Maturity value
₩51,480,500
Principal
₩100,000,000
Pre-tax interest
₩3,500,000
Estimated tax
₩539,000
After-tax interest
₩2,961,000
Maturity value
₩102,961,000

By annual rate

Deposit ₩10,000,000 · 1 year · simple interest · 15.4% standard Korean interest tax

Annual rate
3%
Pre-tax interest
₩300,000
Estimated tax
₩46,200
After-tax interest
₩253,800
Maturity value
₩10,253,800
Annual rate
4%
Pre-tax interest
₩400,000
Estimated tax
₩61,600
After-tax interest
₩338,400
Maturity value
₩10,338,400
Annual rate
5%
Pre-tax interest
₩500,000
Estimated tax
₩77,000
After-tax interest
₩423,000
Maturity value
₩10,423,000

By deposit term

Deposit ₩10,000,000 · 3.5% annual rate · simple interest · 15.4% standard Korean interest tax

Term
1 years
Pre-tax interest
₩350,000
Estimated tax
₩53,900
After-tax interest
₩296,100
Maturity value
₩10,296,100
Term
2 years
Pre-tax interest
₩700,000
Estimated tax
₩107,800
After-tax interest
₩592,200
Maturity value
₩10,592,200
Term
3 years
Pre-tax interest
₩1,050,000
Estimated tax
₩161,700
After-tax interest
₩888,300
Maturity value
₩10,888,300

How it works

Separate principal growth,
interest, and tax.

The interest calculated from the stated rate may differ from what you receive. Subtract interest tax from pre-tax interest, then add your principal to estimate the maturity value. Change the deposit amount, term, and rate to compare deposit scenarios.

  1. Pre-tax interest − interest tax = after-tax interest
  2. Principal + after-tax interest = maturity value
01

How is a lump-sum deposit different from recurring savings?

A lump-sum deposit places all principal at the start, so the full amount earns interest for the entire term. Recurring savings adds money over time, giving each deposit a different interest period.

02

Simple interest and monthly compounding

Simple interest applies only to principal. Monthly compounding includes previously earned interest in later calculations. Select the method stated in the product terms.

03

Tax and deposit protection

The default English estimate does not deduct tax. Enter a custom rate when needed. Deposit insurance coverage depends on the institution, product, and jurisdiction, so verify the applicable protection before opening an account.

04

Depositing ₩10,000,000 for one year at 3.5%

This example uses simple interest and the 15.4% standard Korean interest tax.

Principal
₩10,000,000
Estimated interest
₩296,100
Estimated maturity value
₩10,296,100

Actual results may differ because of day-count conventions, compounding frequency, rounding, taxes, and product terms.

05

Frequently asked questions

Is the annual rate the same as my after-tax return?

No. The stated annual rate is before tax. The term, compounding method, and tax rate change the actual return on principal.

Do all term deposits compound monthly?

No. Many use simple interest or another compounding frequency. Choose monthly compounding only when the product terms say so.

What happens if I withdraw early?

An early-withdrawal rate or penalty may apply. This calculator models a deposit held through maturity.