Current Ibond Rate

I Bond Rates

The rate of an I bond is based on two separate rates, one of which remains constant for the life of the bond, and another linked to changes in the CPI-U measurement. The rate of an I bond changes every 6 months based on the changes in inflation.

Current I Bond Rate for a new bond:

Current rates for a new bond. Valid November 2009 - April 2010

  • Fixed rate: 0.30%
  • Inflation-linked rate: 1.53%
  • Composite rate: 3.36%

Next I bond rate

The next I bond rate change will be on May 1, 2010

  • The fixed rate of a new bond is unknown until the start of the next semiannual period.
  • The inflation-linked rate is based on the CPI-U changes.

    Nov. Rate:
    March April May June July Aug. Sept.
    212.709 213.240 213.856 215.693 215.351 215.834 215.969

    May Rate:
    Sept. Oct. Nov. Dec. Jan. Feb. Mar.
    215.969 216.177 216.330  215.949      

Composition of the I Bond Rate

I Bond rates are based on two factors: the fixed rate and the inflation-linked variable. The fixed rate is established by the Treasury Department by an unknown process. The variable rate is based on the rate of inflation over the past 6 months as measured by the CPI-U. Combined, the fixed rate and the variable rate make up the composite rate of the I Bond. Every six months from the purchase month, an I Bond's rate will change based on the new inflation value. The fixed rate will remain the same throughout the life of the bond.

IBond interest rates are composed of a fixed rate and CPI-U based rate.

The composite rate of a bond will change every 6 months based on the changes in inflation. Since every bond must have 6 full months with the inflation-linked rate active, the composite rate of a bond will not change to reflect the new inflation-linked rate until that bond's six month anniversary. The following chart shows when a bond will change rates for the May and November adjustments based on the issue month of the bond.

Bond Issue Month   May rate goes into effect Nov. rate goes into effect
January   July 1 January 1
February   August 1 February 1
March   September 1 March 1
April   October 1 April 1
May   May 1 November 1
June   June 1 December 1
July   July 1 January 1
August   August 1 February 1
September   September 1 March 1
October   October 1 April 1
November   May 1 November 1
December   June 1 December 1

Example: An I bond purchased in October will begin with a composite rate based on the fixed rate and inflation-linked rate announced in May. On November 1st, the new inflation data is released, but the bond has not reached the six month anniversary, so the rate will not change. On April 1, the October I Bond will change to reflect the new inflation-linked rate announced in November, but will maintain the same fixed rate it had in October. The new composite rate will be comprised of the fixed rate from when the bond was purchased and the inflation-linked rate announced in November. In May, the inflation data will again be announced, but that rate will not go into effect for this October-issued bond until October.

Historical I Bond Fixed Rates

The fixed rate portion of the I Bond is valid for the life of the bond (30 years). The fixed rate combined with the variable rate equals the total rate of the bond for that time.



Fixed Rate History
1-Nov-090.30%
1-May-09 0.10%
1-Nov-080.70%
1-May-080.00%
1-Nov-071.20%
1-May-071.30%
1-Nov-061.40%
1-May-061.40%
1-Nov-051.00%
1-May-051.20%
1-Nov-041.00%
1-May-041.00%
1-Nov-031.10%
1-May-031.10%
1-Nov-021.60%
1-May-022.00%
1-Nov-012.00%
1-May-013.00%
1-Nov-003.40%
1-May-003.60%
1-Nov-993.40%
1-May-993.30%
1-Nov-983.30%
1-Sep-983.40%

Historical CPI-U Linked Rates

Consumer Price Index for all Urban Consumers (CPI-U) is the measurement of inflation that the Fed uses to determine the variable rate of the I Bond's total rate. The CPI-U value is released monthly, but the I Bond rate is only adjusted 2 times per year. I Bonds purchased in November through April use the CPI-U change from March to September. I Bonds purchased between May and October use the CPI-U change from September of the previous year through March.



CPI-U Rate History
1-Nov-091.53%
1-May-09-2.78%
1-Nov-082.46%
1-May-082.42%
1-Nov-071.53%
1-May-071.21%
1-Nov-061.55%
1-May-060.50%
1-Nov-052.85%
1-May-051.79%
1-Nov-041.33%
1-May-041.19%
1-Nov-030.54%
1-May-031.77%
1-Nov-021.23%
1-May-020.28%
1-Nov-011.19%
1-May-011.44%
1-Nov-001.52%
1-May-001.91%
1-Nov-991.76%
1-May-990.86%
1-Nov-980.86%
1-Sep-980.62%

Historical Composite I Bond Rates

The composite rate of the I Bond at any time is based on the Fixed Value and the Variable Value. The Rate is based on the following formula established by the Treasury:

Composite Rate = Fixed rate + 2 * CPI-U Rate +
(Fixed rate * CPI-U Rate)


New I Bond's Initial 6 Month Rate History
1-Nov-093.36%
1-May-090.00%
1-Nov-085.64%
1-May-084.84%
1-Nov-074.28%
1-May-073.74%
1-Nov-064.52%
1-May-062.41%
1-Nov-056.73%
1-May-054.80%
1-Nov-043.67%
1-May-043.39%
1-Nov-032.19%
1-May-034.66%
1-Nov-024.08%
1-May-022.57%
1-Nov-014.40%
1-May-015.92%
1-Nov-006.49%
1-May-007.49%
1-Nov-996.98%
1-May-995.05%
1-Nov-985.05%
1-Sep-984.66%

This graph shows the value of a new I Bond's rate for the first 6 months. After 6 months, the variable rate would change based on changes in the CPI-U rate.

I Bond Rate Calculator

Use this calculator to calculate an I bond's rate. Enter the CPI-U growth rate and the fixed rate you think will be chosen to calculate the I bond's new rate.

I Bond Rate Calculator

CPI-U Increase in %
Fixed Rate in %
New I Bond Rate would be:



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