Inflation: What It Is and Why It Matters

If inflation is 3% per year, something that costs $100 today will cost approximately $103 next year, and $134 in ten years. Your money buys less over time. Inflation is measured by tracking the price of a "basket" of common goods and services, primarily through the Consumer Price Index (CPI).

Why does inflation matter for personal finance? Because it's the invisible tax on idle money. Cash sitting in a current account earning 0.1% interest while inflation runs at 3% is losing 2.9% of its real value every year. Over a decade, this compounds into meaningful wealth erosion.

This is one of the most powerful arguments for investing rather than holding large cash balances. Historically, broad equity markets have returned an average of 7-10% annually — well ahead of inflation — preserving and growing purchasing power over the long term.

Inflation also affects retirement planning directly. A retirement budget of $40,000/year today will need to be significantly larger in 20 or 30 years to maintain the same standard of living. Safe withdrawal rate calculations and FIRE numbers must account for inflation over the full retirement horizon.

Inflation-protected investments — such as Treasury Inflation-Protected Securities (TIPS) in the US, index-linked gilts in the UK, and Series I bonds — adjust their value with inflation, providing a direct hedge for conservative portions of a portfolio.