I Bond Value Calculator

I Bond Value Projection Calculator

Use this calculator to project the future value of your Series I Savings Bonds based on your initial investment, fixed rate, and an assumed average annual inflation rate.









Projected Results:

Projected Value:

Total Interest Earned:

Understanding Series I Savings Bonds

Series I Savings Bonds, commonly known as I Bonds, are a low-risk, liquid savings product issued by the U.S. Treasury. They are designed to protect your investment from inflation, making them an attractive option for long-term savings.

How I Bonds Work

The interest rate on an I Bond is a composite rate, meaning it's made up of two parts:

  1. Fixed Rate: This rate is set when you purchase the bond and remains the same for the life of the bond (up to 30 years). It can be 0% or a positive rate.
  2. Inflation Rate (Variable Rate): This rate is announced twice a year (on May 1st and November 1st) and is based on changes in the Consumer Price Index for all Urban Consumers (CPI-U). This rate adjusts every six months from your bond's issue date.

The composite rate is calculated using the formula: Composite Rate = [Fixed Rate + (2 × Semiannual Inflation Rate) + (Fixed Rate × Semiannual Inflation Rate)]. Here, "Semiannual Inflation Rate" refers to half of the annualized inflation rate announced for that 6-month period. Interest is compounded semi-annually, meaning the interest earned in one six-month period is added to the principal, and the next period's interest is calculated on the new, larger principal.

Using the I Bond Value Projection Calculator

This calculator helps you estimate the future value of your I Bonds. Here's how to use it:

  • Initial Investment: Enter the amount you initially invested in your I Bond. For example, if you bought a $1,000 I Bond, enter 1000.
  • Annual Fixed Rate (%): Input the fixed rate that was applicable when you purchased your I Bond. You can find this on your TreasuryDirect account or purchase confirmation. For instance, if your fixed rate is 0.2%, enter 0.2.
  • Assumed Annual Inflation Rate (%): Since future inflation rates are unknown, this calculator uses an assumed average annual inflation rate for projection. Choose a rate that you believe is realistic for the projection period. For example, if you assume 3% annual inflation, enter 3.0. Keep in mind that actual inflation rates will vary.
  • Projection Years: Specify how many years into the future you want to project the bond's value. I Bonds earn interest for up to 30 years. For a 5-year projection, enter 5.

Important Considerations

  • Accuracy: This calculator provides a projection based on an assumed future inflation rate. Actual returns will depend on the real inflation rates announced by the Treasury.
  • Redemption Penalty: If you redeem an I Bond within the first five years, you will forfeit the last three months of interest. This calculator does not account for this penalty.
  • Taxation: Interest earned on I Bonds is exempt from state and local income taxes. Federal income tax can be deferred until you redeem the bond or it matures.
  • Purchase Limits: There are annual purchase limits for I Bonds (currently $10,000 electronically and $5,000 with tax refund per person per year).

For the most accurate current value of your I Bonds, always refer to your TreasuryDirect account.

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