Inflation vs savings: is your money really growing?

Seeing your savings balance rise feels like progress. But the figure on the statement does not tell you what your money will buy. If prices rise faster than your savings grow, you may have more pounds but less purchasing power. This distinction matters when saving for a home deposit, a large purchase or a long-term financial buffer.

Nominal returns and real returns

A nominal return is the increase in pounds shown in your savings account. A real return takes account of inflation. To estimate purchasing power in today’s money, divide the future savings balance by the cumulative price increase. With a fixed savings rate r, inflation rate i and n years, the future balance is your starting balance × (1 + r)^n, and its real value is that balance ÷ (1 + i)^n.

Subtracting inflation from the interest rate can be a rough one-year shortcut for small rates, but the compound formula is more accurate over several years. For an exact comparison under the fixed-rate assumptions, the real growth factor is ((1 + r)/(1 + i))^n.

Worked example: £10,000 over five years

Change the assumptions: Load a £10,000 example with 4% savings and 3% inflation, then compare it with 2% savings and 5% inflation. Neither inflation assumption is a forecast.

Start with £10,000 earning 4% AER. After five years without additional deposits, the nominal balance is around £12,167. Suppose prices rise by 3% per year over the same period. The cumulative inflation factor is approximately 1.1593, so the future balance has purchasing power of about £10,495 in today’s money. That represents a real gain of about £495, rather than the £2,167 rise visible on the bank statement.

Now consider 2% savings interest alongside 5% annual inflation. The nominal balance still increases, but purchasing power falls because prices are growing faster. Try both cases in the Inflation vs Savings Calculator.

What inflation rate should I use?

The Office for National Statistics (ONS) publishes several inflation measures, including CPI and CPIH. CPIH also incorporates owner-occupiers’ housing costs. They measure changes in prices for defined baskets; they are not personal forecasts. Your spending pattern may be quite different from the average basket, particularly for housing, energy or childcare.

The calculator lets you choose an assumption rather than treating the latest annual inflation reading as a guaranteed future rate. Test a range of scenarios—for example, 2%, 3% and 5%—to see how sensitive your future spending power is to inflation.

Tax, changing rates and long-term goals

Tax can further reduce the interest you keep outside a tax-free account. If the calculator uses the gross AER while you expect tax to be due, your estimated real return may be overstated. Review the Personal Savings Allowance Calculator for an initial tax estimate. Actual savings products can change their interest rates; inflation itself changes month by month, so constant rates are an illustration only.

For a future spending target, remember that today’s £10,000 purchase might cost more in five years. The tool’s ‘savings needed to match inflation’ figure estimates the nominal amount required just to match the purchasing power of the original sum.

Practical way to use the result

• Start with the amount and time horizon for your goal.
• Compare a realistic savings rate with more than one inflation assumption.
• Check the real value, not just the future account balance.
• Allow for tax, fees and the possibility of changing rates.
• Revisit your plan as actual prices and savings products change.

See the ONS inflation and price indices for current statistical context. A historical figure is not a reliable prediction of future inflation.

To turn a future price-adjusted target into a regular saving plan, see monthly savings goal guide.