Future cost and loss of purchasing power over time.
Future cost of that amount
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Real value in today money
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Purchasing power lost
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Worked example
Take R100,000 and an average inflation rate of 5 percent a year over 10 years. Inflation compounds, so prices grow by a factor of 1.05 raised to the power of 10, which is about 1.6289. What costs R100,000 today will cost roughly R162,889 in 10 years. Looked at the other way, R100,000 held as cash for 10 years keeps its number but loses purchasing power: in today's money it is worth R100,000 divided by 1.6289, or about R61,391. That is a loss of R38,609, close to 38.6 percent of the original value. Money sitting idle does not stay still; it quietly shrinks against the price of everything you buy.
| Step | Amount |
|---|---|
| Amount today | R100,000 |
| Inflation factor (1.05 ^ 10) | 1.6289 |
| Future cost of that amount | R162,889 |
| Real value in today money | R61,391 |
How it is calculated
The calculator uses compound inflation, the same mechanism as compound interest but working against you. The inflation factor is one plus the annual rate, raised to the number of years. Multiplying your amount by that factor gives the future cost, what the same goods and services will cost later. Dividing your amount by the factor gives the real value, the purchasing power that today's money retains once prices have risen. The purchasing power lost is the difference between the two, shown in rands and as a percentage. South Africa's headline CPI has spent most of the past decade inside the Reserve Bank's 3 to 6 percent target band, so 5 percent is a reasonable middle assumption, but you can enter any rate. The tool ignores tax and assumes a steady average rate rather than the year-to-year swings real inflation shows.