I-Bond Calculator
See how an I-Bond — a U.S. savings bond that pairs a fixed rate with inflation protection — could grow over time.
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I-Bonds pay you in two parts. The fixed rate is set when you buy and stays with the bond for its whole life. The inflation (variable) rate is reset every 6 months based on inflation, and the Treasury combines the two into a single composite rate — that is what your money actually grows by.
The inflation part protects your purchasing power. When prices rise, the inflation component rises too, so the bond's interest keeps up with the cost of living. That is why people call I-Bonds inflation-protected savings.
Two rules come from the U.S. Treasury. You cannot cash out in the first 12 months at all, and if you cash out before 5 years, you give up the last 3 months of interest. You buy I-Bonds electronically through TreasuryDirect, up to $10,000 per person per calendar year.
This page is for informational purposes only and is not financial, tax, legal, investment, or insurance advice.
Last reviewed: October 2026.