Finance⏱ 6 min read

What Is Inflation and How Does It Affect Your Money?

Inflation silently erodes the purchasing power of money every year. Here's how it's measured, how to calculate its real-world impact on your savings and wages, and what to do about it.

Inflation is one of the most important economic forces affecting your financial life — and one of the least understood. It's not just a news story about rising prices. It directly determines whether your savings are growing or shrinking in real terms.

What Inflation Actually Measures

Inflation measures the rate at which the general level of prices rises over time, which equivalently means the rate at which money loses purchasing power. The UK's headline measure is the Consumer Prices Index (CPI), which tracks a "basket" of around 700 goods and services weighted by how much the average household spends on each.

The Retail Prices Index (RPI) is an older measure, typically 1–2% higher than CPI, and still used for some index-linked products including student loan interest and some rail fares.

The Real Value of Money Over Time

Future value needed to match today's purchasing power: FV = PV × (1 + inflation rate)^years Example: £10,000 today, 3% inflation for 10 years FV = 10,000 × 1.03^10 = 10,000 × 1.3439 = £13,439 To have the same purchasing power in 10 years, you'd need £13,439 — not £10,000.

The Silent Tax on Cash Savings

Cash held in accounts earning less than inflation loses real value every year. This is the "savings trap" — your nominal balance grows, but your purchasing power shrinks.

Real return = Nominal return − Inflation rate Savings account paying 2% during 4% inflation: Real return = 2% − 4% = −2% per year £10,000 after 5 years: Nominal: £10,000 × 1.02^5 = £11,041 Real purchasing power: £10,000 × (0.98)^5 = £9,039 You "gained" £1,041 on paper but lost £961 in real value.

How Inflation Affects Wages

A pay rise below the inflation rate is effectively a pay cut in real terms. This is important context for wage negotiations:

Real wage change = Nominal wage change − Inflation rate 5% pay rise with 7% inflation: Real change = 5% − 7% = −2% real wage cut 3% pay rise with 2% inflation: Real change = 3% − 2% = +1% real wage increase

CPI Basket: What Counts and What Doesn't

The inflation figure you see in the news is an average. Your personal inflation rate depends on your spending pattern. If you spend heavily on:

Energy: More affected when energy prices spike (as in 2021–2023)
Food: Food inflation often diverges significantly from headline CPI
Mortgage: CPI excludes housing costs (CPIH includes owner-occupier costs)
Technology: Electronics have historically had deflation — prices fall over time

Protecting Against Inflation

Equities (shares): Over long periods, equity returns have historically exceeded inflation by 4–7% per year. Companies can generally raise prices with inflation, protecting real earnings.

Index-linked bonds: Government bonds where the payout rises with RPI/CPI. The UK government issues Index-Linked Gilts for this purpose.

Property: House prices have historically kept pace with or exceeded inflation, though with significant regional and cyclical variation.

Cash: Only competitive when nominal interest rates exceed inflation — which does happen, but not always and not for long.

The inflation calculator lets you see exactly how a given inflation rate erodes the value of a specific sum over any time period — useful for planning, salary negotiations, and understanding historical price changes.

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