See exactly how inflation erodes the real value of your savings — and what interest rate you need to earn just to maintain purchasing power. The gap between your savings rate and inflation is the true cost of conservative saving.
| Year | Nominal Balance | Real Value | Purchasing Power |
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The number on your savings account statement shows nominal value — what your balance is in today's pounds. But what actually matters is real value — what those pounds can buy. When inflation runs at 3% and your account pays 2%, your nominal balance grows while your purchasing power shrinks. This tool makes that erosion visible, shows you exactly how much purchasing power you lose over any period, and calculates the break-even rate you need to at least maintain the real value of your savings.
The break-even rate is the gross AER you need to earn so that, after tax, your real purchasing power remains unchanged. Formula: Break-even gross rate = Inflation rate ÷ (1 - tax rate). For a higher-rate (40%) taxpayer with 3% inflation: 3% ÷ 0.6 = 5.0% AER required just to break even. At 4.5% AER, they lose real value. For a basic-rate (20%) taxpayer: 3% ÷ 0.8 = 3.75% AER required.
Nominal return: the stated interest rate on your account — what the bank pays you. Real return: your nominal return minus inflation. If you earn 4.5% but inflation is 3%, your real return is approximately 1.5% (more precisely: (1.045/1.03)-1 = 1.46%). This is the actual increase in your purchasing power.
Inflation above your savings rate is effectively a tax on wealth held in cash. £20,000 in a 2% account with 4% inflation loses approximately £400 in real value per year. Over 10 years that erosion compounds to nearly £3,200 lost in purchasing power — despite the nominal balance rising. This is why holding large cash balances in low-rate accounts is financially costly.
The nominal rate is what your savings account pays — the stated AER. The real rate is the nominal rate minus inflation, showing the actual increase in purchasing power. At 4.5% AER with 3% inflation: real rate ≈ 1.46%. Your money buys 1.46% more than it did a year ago in real terms. If inflation exceeds your nominal rate, the real rate is negative and your purchasing power is falling despite a growing balance.
UK CPI inflation peaked at 11.1% in October 2022, fell to around 4% by end of 2023, and is projected at 2.5–3.5% in 2026. The Bank of England targets 2% CPI inflation. For long-term projections, 2–3% is a reasonable central estimate, though short-term forecasts can vary significantly.
Options include: (1) Maximise the savings rate — compare accounts regularly and switch to the best easy-access or fixed rate; (2) Use index-linked savings certificates (NS&I when available); (3) Invest in equities for long-term money — equities have historically beaten inflation over rolling 10-year periods; (4) Hold inflation-linked bonds (gilts) for medium-term savings. For short-term savings (under 3 years), a competitive fixed-rate bond is the most practical option.