Most people think of saving as protective. You put money somewhere safe, it stays there, and when you come back for it, it is still there. This intuition is correct in nominal terms — the number in the account does not shrink. But in real terms, in terms of what that number can actually buy, money left in a low-yield account shrinks every year, automatically, without requiring any bad luck or bad decisions.
This is inflation: the gradual decline in the purchasing power of money over time.
What inflation actually is
Inflation is the rate at which the general price level of goods and services rises. When inflation is running at 3%, something that cost £100 this year will cost approximately £103 next year. Your money is the same; what it can buy is less.
Central banks in most developed economies target inflation of around 2% per year as a desirable level — enough to encourage spending and investment, low enough to be manageable. In practice, inflation varies considerably: during 2021-2023, many economies experienced inflation of 7-11% as supply chains disrupted and energy prices spiked. In other periods, inflation has run below target.
The inflation rate that matters for your finances is the one experienced by your specific spending basket. If you own a home, your housing costs may not rise much. If you rent, your costs may rise with the rental market. If you drive, fuel and car costs matter. The official inflation measure is a useful reference, but your personal inflation rate is what affects your actual purchasing power.
The invisible tax
The reason inflation is often called an invisible tax is that it operates without any visible transaction. No government takes money from your account. No invoice arrives. The money is just quietly worth less.
Consider a concrete example. You have £10,000 in a current account earning 0% interest (still common in many accounts). Inflation runs at 3% per year. After one year, your balance is still £10,000 — but it can buy what £9,700 could have bought a year ago. You have lost £300 in real terms without losing a single pound nominally.
Over ten years at 3% inflation, the purchasing power of that £10,000 drops to approximately £7,400. You have effectively lost £2,600 without any visible event.
This is why financial advisers say cash is not risk-free. Cash is free of market risk — its nominal value does not fluctuate. But it is fully exposed to inflation risk, and inflation is a certainty rather than a possibility.
How inflation compounds
Compounding works on inflation exactly as it works on interest — meaning the effects accumulate over time rather than adding linearly.
A 2% inflation rate over 35 years reduces purchasing power by approximately 50%. Something that costs £50,000 today would cost approximately £100,000 in 35 years. Something that costs £500 today would cost approximately £1,000. This is the timescale relevant for retirement planning — and it means that a retirement fund calculated in today’s prices must either generate returns that exceed inflation or it will be worth much less in real terms than the nominal balance suggests.
Higher inflation rates produce dramatically faster erosion. At 5% annual inflation, purchasing power halves in roughly 14 years. At 10%, it halves in about 7 years.
Assets that beat inflation
The practical response to inflation is to hold assets whose value or returns grow at least as fast as the inflation rate. This is the fundamental reason why investing — rather than saving in cash — is essential for long-term financial health.
Equities (shares) have historically produced real returns (above inflation) of approximately 4-7% per year over long periods, though with significant short-term volatility. This long-term outperformance of inflation is one of the primary reasons equity investment is recommended for long-horizon goals.
Property has historically maintained or grown real value in many markets, though it is illiquid and requires significant capital.
Index-linked bonds (gilts linked to inflation, or I-bonds) provide guaranteed protection against inflation by definition — the principal and interest payments adjust with the inflation rate. They are low-risk but provide no real return above inflation.
Gold and other commodities have historically served as inflation hedges over very long periods, but with high short-term volatility and no income generation.
High-yield savings accounts and term deposits, when rates are favourable, can match or slightly exceed inflation on an after-tax basis. During periods of high interest rates (such as 2022-2024), these offered meaningful real returns without market risk.
The practical implication
The practical takeaway is straightforward: money you will not need for more than five years should not be sitting in a standard current account. The guaranteed outcome of leaving it there is a real loss of value, year after year, at whatever rate inflation is running.
Money you will need within one to two years (emergency fund, near-term planned expenses) should be in a high-yield savings account — earning as much as possible while remaining safe and accessible.
Money you will not need for five or more years should be invested, because only assets with real return potential can reliably outpace inflation over long periods.
This is not a counsel of risk. It is a recognition that the apparently safe option — doing nothing — is in fact a slow, guaranteed erosion of your financial position. The choice is not between risk and safety. It is between different types of risk: market volatility on one side, inflation erosion on the other.
