Enter your savings balance, rates and inflation. See the real return and what investing would build.
This calculator shows the future purchasing power of money sitting in a savings account or under-a-mattress account — how many real dollars your savings will be worth after inflation erodes them over time. It's for savers who feel safe keeping large cash balances and haven't quantified how much spending power they're losing to inflation each year.
Real purchasing power = Nominal Balance × (1 / (1+i)^n), where i is the annual inflation rate and n is years. If your savings account pays 4.5% but inflation is 3.5%, your real return is approximately 1% — you're not losing money nominally, but you're barely preserving purchasing power. At the US historical average inflation rate of 3%, $100,000 in cash has only $74,000 in purchasing power after 10 years.
Cash feels safe because the number doesn't change — your account still says $100,000. But the purchasing power of that money declines silently every year. Over the 2022–2023 inflation surge, someone holding $100,000 in a 0.5% savings account lost approximately $7,500 in real purchasing power in a single year. This calculator makes that invisible erosion visible so you can decide whether your cash holdings are the right size.