6.3325
%
$9,326.59
$4,326.59
$8,374.74
$5,000.00
$5,000.00
6.3325
%
$9,326.59
$4,326.59
$8,374.74
$5,000.00
$5,000.00
The Savings Bond Calculator projects the future value of U.S. Series I Savings Bonds, the inflation-protected government bonds that have become one of the most popular safe-haven investments. Series I bonds earn a composite interest rate that combines a fixed rate (set at purchase, never changes) with a semiannual inflation rate (adjusted every May and November based on CPI-U data).
Series I bonds are issued by the U.S. Department of the Treasury and are backed by the full faith and credit of the United States government, making them among the safest investments in the world. They are designed to protect your purchasing power against inflation — when inflation rises, so does your bond's interest rate.
The composite rate formula for I bonds is: Composite Rate = Fixed Rate + (2 × Semiannual Inflation Rate) + (Fixed Rate × Semiannual Inflation Rate). For example, with a 1.3% fixed rate and a 2.5% semiannual inflation rate, the composite rate is approximately 6.38%. Interest compounds semiannually and is paid when the bond is redeemed.
Key rules for I bonds: you can purchase up to $10,000 per person per calendar year in electronic bonds (plus $5,000 in paper bonds via tax refund). The minimum holding period is one year, and bonds redeemed before 5 years forfeit the last 3 months of interest. After 5 years, there is no penalty. Bonds earn interest for up to 30 years.
I bonds have gained significant attention during periods of high inflation, as their rates can exceed 5-9% when inflation is elevated. Even when inflation moderates, the fixed rate component ensures a base return above zero. This makes I bonds particularly attractive compared to savings accounts and CDs when inflation is high.
This calculator helps you project bond values based on assumed fixed and inflation rates. Since the inflation component changes every 6 months, actual results will vary from projections. Use the current composite rate from TreasuryDirect.gov for the most accurate near-term estimates.
The calculator uses the I Bond composite rate formula:
Composite Rate = Fixed Rate + (2 × Inflation Rate) + (Fixed Rate × Inflation Rate)
Interest compounds semiannually: Value = Purchase Amount × (1 + Composite Rate / 2)^(2 × Years)
Note: The inflation component changes every 6 months, so long-term projections assume a constant rate for estimation purposes.
The current value shows your bond's projected worth after the holding period. The composite rate combines fixed and inflation components — higher composite rates indicate strong inflation protection. Remember that bonds redeemed before 5 years lose the last 3 months of interest.
Inputs
Results
$10K I Bond at ~6.33% composite rate grows to ~$18,576 in 10 years
Inputs
Results
Two $5K bonds at ~5.02% composite grow to ~$13,382 in 5 years
A Series I bond is a U.S. government-backed savings bond designed to protect against inflation. It earns a composite interest rate combining a fixed rate and a variable inflation-adjusted rate, updated semiannually.
You can purchase up to $10,000 in electronic I bonds per person per calendar year through TreasuryDirect. An additional $5,000 in paper bonds can be purchased using your tax refund.
I bonds must be held for a minimum of 1 year. If redeemed before 5 years, you forfeit the last 3 months of interest. After 5 years, there is no penalty. Bonds earn interest for up to 30 years.
The fixed rate is set by the Treasury at purchase and never changes. The inflation rate is adjusted every May 1 and November 1 based on changes in the Consumer Price Index (CPI-U).
I bond interest is subject to federal income tax but exempt from state and local taxes. You can defer taxes until redemption or report annually. Interest used for qualified education expenses may be tax-free.
The composite rate can never go below zero, even if deflation occurs. The fixed rate provides a floor. However, during deflation, the composite rate could be reduced to 0% (but never negative).
Electronic I bonds are purchased at TreasuryDirect.gov. Paper I bonds can only be purchased with your federal tax refund using IRS Form 8888.
I bonds are simpler and have no market risk (no price fluctuation), but are limited to $10K/year. TIPS are Treasury securities that trade on the market with higher limits but price volatility.
After 30 years, I bonds stop earning interest. You should redeem them at that point to avoid missing out on returns from reinvestment.
Yes, you can purchase I bonds as gifts for others through TreasuryDirect. Gift bonds do not count against the recipient's annual purchase limit until they are delivered.
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