Inflation Calculator
The quiet tax on cash: see what today's dollars will buy in the future — or what a past amount would need to be today — at any inflation rate.
The inflation formulas
Today's equivalent of past money = Amount × (1 + inflation)years
$10,000 held as cash for 20 years at 3% inflation:
Buying power = 10,000 ÷ 1.0320 = 10,000 ÷ 1.806 = $5,537 — cash quietly loses almost half its value.
A starting salary of $35,000 in 1990 — 35 years ago — at an assumed 3% average inflation rate. What's the equivalent today?
Today's equivalent = 35,000 × 1.0335 = 35,000 × 2.8149 = $98,521. A $98,521 salary today represents the same purchasing power as that 1990 salary — anything less is a real pay cut relative to 1990, even if the dollar figure looks much larger.
Common inflation mistakes
- Comparing dollar amounts across decades without adjusting for inflation. As the salary example shows, a bigger nominal number today can still represent less real purchasing power than an older, smaller-looking figure.
- Assuming a fixed "halving time" means erosion is linear. Inflation compounds — purchasing power drops faster in later years even at a constant rate, since each period's loss applies to an already-smaller base (see the FAQ on this below).
- Ignoring inflation when setting a long-term dollar goal. A retirement or savings target set only in today's dollars will fall well short of its intended real value by the time it's needed, unless it's adjusted upward for expected inflation first.
What 3% inflation does over a lifetime
| Years | $100 buys the equivalent of… | Prices have risen… |
|---|---|---|
| 10 | $74 | +34% |
| 20 | $55 | +81% |
| 30 | $41 | +143% |
| 40 | $31 | +226% |
This is why every long-term plan must be inflation-aware: a retirement target set in today's dollars needs to roughly double for a retirement 25 years away, wage negotiations below inflation are pay cuts, and "safe" cash savings earning less than inflation are guaranteed real losses. The defense is owning things that reprice with inflation — equities, TIPS, I-Bonds, real assets — for money you won't need soon. See real vs. nominal comparisons in the investment calculator.
Frequently asked questions
How much does inflation reduce my money's value?
At 3%: $100 → $74 of buying power in 10 years, $55 in 20, $41 in 30.
What is the average inflation rate?
Roughly 3%/yr in the U.S. over the past century; 2.5–3% is the standard planning assumption.
How do I protect savings from inflation?
Cash for near-term needs only; long-term money in assets that historically outpace inflation (stocks, TIPS, I-Bonds, real assets).
How do I find today's equivalent of a past salary or price?
Past amount × (1 + rate)^years. $35,000 from 1990 (35 years, 3%) equals about $98,521 today.
Why does inflation's effect seem to accelerate?
It compounds — each halving applies to an already-smaller base, so later decades lose purchasing power faster even at a constant rate.
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Note: Uses a constant assumed rate rather than historical CPI data; actual inflation varies year to year. Not financial advice. Last reviewed: September 2026.