Inflation Impact Calculator

Inflation and purchasing power — what the numbers actually mean

Inflation is the gradual increase in the general price level of goods and services over time. It is most commonly measured by the consumer price index (CPI), which tracks the cost of a representative basket of goods and services that households typically buy. When inflation runs at 3% per year, something that costs 100 today will cost approximately 103 in a year, 106.09 in two years, and so on. The compounding effect means that even modest annual inflation rates produce significant purchasing power erosion over longer time horizons.

For most people, inflation is an abstract concept until they see the numbers applied to something concrete. This calculator applies the compound inflation formula to any amount you choose, showing both the equivalent future cost — how much you would need in the future to buy what your current amount buys today — and the future real value of your current amount, meaning how much today's money will actually be worth after inflation has run for the specified period. The difference between these two figures is the purchasing power you lose to inflation.

The compound inflation formula

The calculation uses compound growth: future equivalent equals present value multiplied by (1 + inflation rate) to the power of the number of years. For example, at 3% inflation over 20 years, a basket of goods costing 10,000 today would cost approximately 18,061 in 20 years. Conversely, 10,000 in savings sitting in a non-interest-bearing account would have the real purchasing power of only about 5,537 in today's money after those same 20 years. This is why leaving money in low-yielding accounts while inflation runs at historically normal rates constitutes a slow, silent erosion of wealth.

What inflation rate to use

If you are modelling future costs for planning purposes, using the long-term average inflation rate for your country is usually the most appropriate starting point. For most developed economies, this is in the range of 2–3% per year over multi-decade periods, though actual inflation varies substantially from year to year and across different categories of spending. Healthcare, education, and housing costs have historically inflated faster than the general CPI in many countries; food and electronics tend to be closer to the general rate or below it. If you are modelling a specific expense category, you may want to use a rate that reflects that category's historical trend rather than the general CPI.

Why inflation matters for savings and retirement planning

The inflation impact calculation is particularly important for retirement planning. A retirement income that feels comfortable today will buy meaningfully less in twenty or thirty years if it is not adjusted for inflation. Someone planning to retire on a fixed income of 3,000 per month should note that at 3% annual inflation, that 3,000 will have the purchasing power of only about 1,656 in today's money after 20 years. Retirement income that is not indexed to inflation effectively declines in real value every year.

This is one reason why financial planners emphasise investing in assets that tend to appreciate at or above the rate of inflation — equities, real estate, inflation-linked bonds — rather than holding all savings in cash or low-yield savings accounts. Cash in a savings account earning 1% interest while inflation runs at 3% results in a negative real return of approximately 2% per year, meaning purchasing power is being eroded even as the nominal balance increases.

Inflation and large purchases

Inflation calculations are also useful for timing large purchases. If you are planning to buy something expensive — a vehicle, renovations, a holiday — comparing the current cost with the projected future cost at realistic inflation rates can help you decide whether to buy sooner or save for longer. In categories where prices are rising faster than average, waiting can genuinely cost more. In categories where technology drives prices down over time, such as consumer electronics, the calculation tips the other way.

Using inflation data for salary negotiations

A practical but often overlooked application is salary planning. If your salary does not increase by at least the rate of inflation each year, your real income — your purchasing power — is declining even if your nominal salary stays the same. Using this calculator with your current salary, the current inflation rate, and a multi-year horizon makes visible the cumulative real wage loss of a below-inflation pay settlement. A pay rise of 2% in a 4% inflation environment is effectively a 2% real pay cut. Over several years, this compounds to a significant reduction in real income.