Inflation doesn’t feel dramatic day to day, which is exactly why it’s easy to underestimate its long-term effect on money sitting in a low-interest account. Here’s what it actually does to $10,000 over time.
The Setup
$10,000 sitting in a traditional savings account earning 0.05% APY. Assume an average annual inflation rate of 3% (a reasonable long-run average, even though any single year can run higher or lower).
What Happens to the Number vs. What Happens to the Value
After 10 years, the account balance (nominal value) has grown to roughly $10,050 — inflation-adjusted for the negligible interest earned. But because prices have risen at an average of 3% a year over that same decade, the same $10,050 now buys what roughly $7,480 would have bought 10 years earlier, based on the 3% annual erosion of purchasing power. The account balance went up slightly; the actual purchasing power dropped by about 25%.
The Same Money, Invested Instead
If that same $10,000 had instead been invested at an average 7% annual return (a commonly cited long-run average for a diversified stock index fund) over the same 10 years, the nominal balance would grow to roughly $19,700. After adjusting for 3% average annual inflation, the real (inflation-adjusted) purchasing power would be approximately $14,650 — meaningfully more than the original $10,000, unlike the savings account scenario where purchasing power actually fell.
Why This Matters More for Long-Term Money Than Short-Term Money
For an emergency fund you might need within the next year or two, this trade-off doesn’t apply the same way — you need stability and access more than growth, and a high-yield savings account (not a low-rate one) is still the right tool, even if it doesn’t fully outpace inflation. But for money you won’t touch for 10, 20, or 30 years, leaving it in a low-interest account isn’t a «safe» choice in the way it feels — it’s a choice that reliably loses purchasing power over time, even though the number on the statement never goes down.
A Common Misconception
People often describe a savings account as «risk-free,» but that framing only accounts for the risk of the number going down. It ignores the near-certainty that purchasing power erodes when the interest rate is meaningfully below the inflation rate — which is the situation for most traditional savings accounts. A high-yield savings account at 4% is a genuinely different case, since it can outpace or roughly match typical inflation, unlike the 0.05% example above.
The Practical Takeaway
The right account for money depends on the timeline: short-term money belongs in a high-yield savings account for stability and access; long-term money that can tolerate short-term ups and downs has historically fared much better against inflation when invested rather than left to sit at near-zero interest.