DONNOKWhat will 100 million won be worth in 10 years? Future purchasing power calculator
At 3.161% inflation, 100 million won keeps 73.3% of its value after 10 years. How DONNOK’s calculator works, with results for 2%, 3% and 5%.
What is future purchasing power?
Future purchasing power expresses money you will have later in today’s prices. One hundred million won is still 100 million won in 10 years, but if prices rise in the meantime, it will buy less than 100 million won buys today.
To compare a future amount with today, you discount it by the inflation rate. The calculator does that discounting in one step.
Where is the calculator and how do I use it?
The calculator works independently of your registered funds and does not save what you enter, so you can try as many amounts as you like.
- Open Future purchasing power calculator in the Settings tab.
- Enter an amount. It starts at 100,000,000.
- Enter a duration between 0 and 100 years.
- Keep Use the latest five years of CPI, or turn it off and enter your own annual inflation rate from −20% to 100%.
- Tap Calculate to see the estimated purchasing power, the difference from today and the percentage of current purchasing power.
How is the five-year CPI default calculated?
The default compares the consumer price index for the latest observed month with the index exactly 60 months earlier and converts it to an average annual compound rate. The index is the all-items CPI (2020 = 100), compiled by Statistics Korea and published in the Bank of Korea’s Economic Statistics System (ECOS).
When the screenshots above were taken, the data showed 102.75 for August 2021 and 120.05 for August 2026. (120.05 ÷ 102.75)^(1/5) − 1 ≈ 3.161%, which became the default. When new CPI data is published and the app’s data updates, the period and rate change, so your screen may show a different value.
The result is 100,000,000 ÷ 1.03161^10 ≈ 73,256,230 won. The app treats a year as 365 days and applies the same formula over time, so you can enter a fractional number of years.
What is 100 million won worth after 10 years at different inflation rates?
The same 100 million won ends up with very different values depending on the rate you assume. The figures below were checked with the calculator’s formula.
| Annual inflation | Value in today’s prices | Share of today |
|---|---|---|
| −1% | About 110.57 million won | 110.6% |
| 2% | About 82.03 million won | 82.0% |
| 3% | About 74.41 million won | 74.4% |
| 3.161% (five-year example) | About 73.26 million won | 73.3% |
| 5% | About 61.39 million won | 61.4% |
What should I keep in mind when reading the result?
The calculation assumes one rate for the whole period. Real inflation changes from year to year, and the inflation you personally feel can differ from the CPI depending on what you buy.
The calculator does not add interest or investment returns. To see how interest offsets inflation, compare the interest rate with the inflation rate. The My display board follows the actual monthly CPI path, so it will not match a calculator result that uses a single rate.
A negative inflation rate makes the result larger than the original amount: when prices fall, the same money buys more.