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What inflation, fees and taxes change
Updated 4 November 2026 · Educational content
The number shown by the calculator is a nominal balance: a future euro amount before costs and tax. It is not a measure of what those euros will buy. Inflation, charges and tax can each reduce the practical benefit.
Inflation: the same number buys less
If prices rise by 2% each year, €1,000 received in twenty years has buying power equivalent to about €673 today. This is calculated as €1,000 divided by 1.02 to the power of twenty. The 2% figure is an illustration, not a forecast.
To convert a nominal return into an inflation-adjusted return, use (1 + nominal return) / (1 + inflation) − 1. A 5% nominal return with 2% inflation is about 2.94% in real terms, rather than exactly 3%. Our main calculator does not perform this adjustment automatically.
Fees: small percentages have a long timeline
For a simple illustration, €1,000 growing at a constant 5% for twenty years becomes about €2,653. At 4%, it becomes about €2,191. The difference is about €462. These are two hypothetical net growth rates; actual fee calculations depend on the product and when charges are applied.
Check ongoing fund charges, platform fees, trading costs and currency conversion charges. A flat transaction fee can be especially significant for a very small contribution. The SEC explains different fee types in its guide to understanding fees.
Tax: there is no universal rate
Tax treatment depends on where you are tax resident, the investment, the account structure and when income or gains arise. A single after-tax percentage would give a misleading impression of precision. This tool does not estimate tax or determine whether a particular investment is suitable for you.
For Irish tax information, start with Revenue and look up the rules for the specific investment you are considering. Do not assume that a share, an ETF and a pension receive the same treatment. Seek qualified advice when the classification or your circumstances are unclear.
Use the headline number carefully
Record the assumed rate and timeline alongside any result you save. Compare a lower-rate scenario as well. When a goal requires a particular amount of spending power, build a plan that explicitly considers inflation and costs rather than relying on the largest calculator figure.
See all calculator assumptions or read about market risk and uncertain returns.