Professor Zvi Bodie, a finance professor at Boston University, said that Treasury securities were better for retirement savers because Treasuries eliminated the risk of default. He and Shane A. Chalke, an expert on annuities, favor two types of inflation-protected Treasury securities that were created in 1997, TIPS and I bonds.

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Consumer Price Index for All
Urban Consumers (CPI-U)

Changes in the CPI-U are used to determine the inflation-linked rate of an I bond. An I bond will adjust rates semiannually to track the previous 6 months' change in inflation as measured by a percent change in the CPI-U value.

What is CPI-U?

The Consumer Price Index (CPI) is the statistical metric developed by the Bureau of Labor Statistics used to monitor the change in the price of a set list of products. The idea is that by monitoring the fluctuations in price it costs to purchase a set basket of goods, the government can track the cost of living for most individuals. The CPI-U is the CPI value for Urban Consumers, which excludes rural populations and represents approximately 80% of the population. The CPI and CPI-U do not directly measure inflation, but it gives a very good idea of whether we are in a period of inflation or deflation and how severe that change may be. As the Bureau of Labor Statistics states, "The CPI is generally the best measure for adjusting payments to consumers when the intent is to allow consumers to purchase at today's prices, a market basket of goods and services equivalent to one that they could purchase in an earlier period."

Many argue that the CPI-U is not a very good measurement of inflation in today's society. The CPI-U excludes the cost of energy and food, which have steadily risen over time. Regardless, the CPI-U is the metric used by the Treasury for calculating the inflation-linked rate of an I Bond.

CPI-U Measurements

This table shows the CPI-U changes since 1998, when I Bonds were first released. I Bonds use the change in these numbers to determine the inflation-linked portion of the bond's rate. Bonds released in November through April use the CPI-U change from March to September. Bonds purchased between May and October use the CPI-U changes from September of the previous year through March.

For more detailed information on CPI-U, including charts for each year, visit CPI-U.info.

YearJanFebMarAprMayJunJulAugSepOctNovDec
1998161.6161.9162.2162.5162.8163.0163.2163.4163.6164.0164.0163.9
1999164.3164.5165.0166.2166.2166.2166.7167.1167.9168.2168.3168.3
2000168.8169.8171.2171.3171.5172.4172.8172.8173.7174.0174.1174.0
2001175.1175.8176.2176.9177.7178.0177.5177.5178.3177.7177.4176.7
2002177.1177.8178.8179.8179.8179.9180.1180.7181.0181.3181.3180.9
2003181.7183.1184.2183.8183.5183.7183.9184.6185.2185.0184.5184.3
2004185.2186.2187.4188.0189.1189.7189.4189.5189.9190.9191.0190.3
2005190.7191.8193.3194.6194.4194.5195.4196.4198.8199.2197.6196.8
2006198.3198.7199.8201.5202.5202.9203.5203.9202.9201.8201.5201.8
2007202.416203.499205.352206.686207.949208.352208.299207.917208.490208.936210.177210.036
2008211.080211.693213.528214.823216.632218.815219.964219.086218.783216.573212.425210.228
2009211.143212.193212.709213.240213.856215.693215.351215.834215.969216.177216.330215.949
2010216.687216.741217.631218.009 218.178 217.965 218.011 218.312 218.439 218.711 218.803 219.179
2011 220.223 221.309 223.467 224.906 225.964 225.722 225.922 226.545 226.889 226.421 226.230 225.672
2012 226.665 227.663 229.392 230.085 229.815 229.478 229.104 230.379 231.407 231.317 230.221 229.601
2013 230.280 232.166 232.773 232.531 232.945 233.504 233.596 233.877 234.149 233.546 233.069 233.049
2014 233.916 234.781 236.293 237.072 237.900 238.343 238.250 237.852 238.031 237.433 236.151 234.812
2015 233.707 234.722 236.119 236.599 237.805 238.638 238.654 238.316 237.945 237.838 237.336 236.525
2016 236.916 237.111 238.132 239.261 240.229 241.018 240.628 240.849 241.428 241.729 241.353 241.432
2017 242.839 243.603 243.801          

CPI-U since I Bond's first issued

CPI-U for the past 2 years

The following table shows changes in CPI-U as a percentage, which is the value used in the I Bond rate calculation.

Issue DateCPI-U/Inflation Rate
May 2017 0.98%
November 2016 1.38%
May 2016 0.08%
November 2015 0.77%
May 2015 -0.8%
November 2014 0.74%
May 2014 0.92%
November 2013 0.59%
May 2013 0.59%
November 2012 0.88%
May 2012 1.10%
November 2011 1.53%
May 2011 2.30%
November 2010 0.37%
May 2010 0.77%
November 2009 1.53%
May 2009 -2.78%
November 2008 2.46%
May 2008 2.42%
November 2007 1.53%
May 2007 1.21%
November 2006 1.55%
May 2006 0.50%
November 2005 2.85%
May 2005 1.79%
November 2004 1.33%
May 2004 1.19%
November 2003 0.54%
May 2003 1.77%
November 2002 1.23%
May 2002 0.28%
November 2001 1.19%
May 2001 1.44%
November 2000 1.52%
May 2000 1.91%
November 1999 1.76%
May 1999 0.86%
November 1998 0.86%
September 1998 0.62%

CPI-U Calculators

Based on the values of CPI-U, this calculator lets you determine the CPI-U linked rate for an I-bond. November I bonds use the change in CPI-U from March to September. May I bonds use the change from September of the previous year to March.

November I-Bond
March CPI-U
September CPI-U
CPI-U Increase
May I-Bond
September CPI-U
March CPI-U
CPI-U Increase

Use this calculator to find the rate of an I-bond given the above CPI-U increase and the fixed rate of the bond.

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





Page last modified 9/1/2011