Inflation Impact Savings Calculator

Nominal growth vs. what it's actually worth after inflation

$20,000 earning a 4.2% nominal annual yield over 8 years grows to $27,795.32 in account-statement dollars. But against 3% annual inflation, that same growth is only worth $21,941.89 in today's purchasing power -- a real annual return of just 1.17%, far below the 4.2% the account statement shows.

That gap between nominal (27,795.32) and real (21,941.89) is the entire point of this calculator: a savings account can show consistent growth on paper while barely outpacing, or even losing to, inflation in terms of what that money can actually buy.

Real annual rate isn't simply nominal minus inflation (4.2% - 3% = 1.2%) -- it's calculated by comparing the actual compounded nominal and real ending values, which is why the result (1.17%) is slightly below that simple subtraction.

Why 1.17% real return matters more than 4.2% nominal

Nominal yield minus inflation, compounded. Not FDIC or product advice. A savings account advertising 4.2% APY sounds attractive until you compare it to inflation -- at 3% inflation, the real growth rate of 1.17% is what actually determines whether your money is gaining or losing ground.

This gap narrows or reverses entirely depending on the rate environment: when inflation runs above the account's nominal yield, the real rate goes negative even though the account balance keeps growing every month.

Principal and years must both be greater than zero for the compounding math to run.

Comparing this account to alternatives

If 4.2% isn't the best rate available, comparing several accounts' nominal APY side by side is a faster first step -- the High-Yield Savings APY Comparator does that directly.

For the reverse view of this same erosion -- what a fixed dollar amount is worth later without any interest offsetting it -- see the Inflation Adjusted Purchasing Power Calculator.

Frequently Asked Questions (FAQ)