Treasury resets the Series I savings bond inflation rate on Nov 1, 2026 using its published formula: the semiannual inflation rate is the change in the not-seasonally-adjusted CPI-U from Mar 2026 to Sep 2026, rounded to 0.01%; the variable rate is twice that; the composite rate is fixed + 2 × semiannual + fixed × semiannual. With CPI-U Mar 2026 = 330.213 (actual) and Sep 2026 projected at 334.666 (projected), the semiannual rate is 1.35% and the variable rate 2.7% (scenarios: engine 2.7%, flat 2.96%, gauge model 2.84%). At the last confirmed fixed rate of 0.9% (announced Nov 1, 2025) the composite would be 3.61%; the page lets you enter the fixed rate Treasury actually sets. Aug 2026 is the Nowflation CPI nowcast (0.281% SA MoM), printing Sep 11, 2026; the rate in force now (announced May 2026) is 3.34% variable.
Checked against Treasury's published rates: 12 of 12 match to the basis point.
| Announced | CPI-U from → to | Semiannual | Variable | Treasury |
|---|---|---|---|---|
| May 2026 | Sep 2025 324.8 → Mar 2026 330.213 | 1.67% | 3.34% | — |
| Nov 2025 | Mar 2025 319.799 → Sep 2025 324.8 | 1.56% | 3.12% | 1.56% |
| May 2025 | Sep 2024 315.301 → Mar 2025 319.799 | 1.43% | 2.86% | 1.43% |
| Nov 2024 | Mar 2024 312.332 → Sep 2024 315.301 | 0.95% | 1.9% | 0.95% |
| May 2024 | Sep 2023 307.789 → Mar 2024 312.332 | 1.48% | 2.96% | 1.48% |
| Nov 2023 | Mar 2023 301.836 → Sep 2023 307.789 | 1.97% | 3.94% | 1.97% |
| May 2023 | Sep 2022 296.808 → Mar 2023 301.836 | 1.69% | 3.38% | 1.69% |
| Nov 2022 | Mar 2022 287.504 → Sep 2022 296.808 | 3.24% | 6.48% | 3.24% |
| May 2022 | Sep 2021 274.31 → Mar 2022 287.504 | 4.81% | 9.62% | 4.81% |
| Nov 2021 | Mar 2021 264.877 → Sep 2021 274.31 | 3.56% | 7.12% | 3.56% |
| May 2021 | Sep 2020 260.28 → Mar 2021 264.877 | 1.77% | 3.54% | 1.77% |
| Nov 2020 | Mar 2020 258.115 → Sep 2020 260.28 | 0.84% | 1.68% | 0.84% |
| May 2020 | Sep 2019 256.759 → Mar 2020 258.115 | 0.53% | 1.06% | 0.53% |
| Nov 2019 | Mar 2019 254.202 → Sep 2019 256.759 | 1.01% | 2.02% | — |
| May 2019 | Sep 2018 252.439 → Mar 2019 254.202 | 0.7% | 1.4% | — |
| Nov 2018 | Mar 2018 249.554 → Sep 2018 252.439 | 1.16% | 2.32% | — |
| May 2018 | Sep 2017 246.819 → Mar 2018 249.554 | 1.11% | 2.22% | — |
| Nov 2017 | Mar 2017 243.801 → Sep 2017 246.819 | 1.24% | 2.48% | — |
| May 2017 | Sep 2016 241.428 → Mar 2017 243.801 | 0.98% | 1.96% | — |
| Nov 2016 | Mar 2016 238.132 → Sep 2016 241.428 | 1.38% | 2.76% | — |
| May 2016 | Sep 2015 237.945 → Mar 2016 238.132 | 0.08% | 0.16% | — |
| Nov 2015 | Mar 2015 236.119 → Sep 2015 237.945 | 0.77% | 1.54% | — |
| May 2015 | Sep 2014 238.031 → Mar 2015 236.119 | -0.8% | -1.6% | — |
| Nov 2014 | Mar 2014 236.293 → Sep 2014 238.031 | 0.74% | 1.48% | — |
| May 2014 | Sep 2013 234.149 → Mar 2014 236.293 | 0.92% | 1.84% | — |
| Nov 2013 | Mar 2013 232.773 → Sep 2013 234.149 | 0.59% | 1.18% | — |
| May 2013 | Sep 2012 231.407 → Mar 2013 232.773 | 0.59% | 1.18% | — |
| Nov 2012 | Mar 2012 229.392 → Sep 2012 231.407 | 0.88% | 1.76% | — |
| May 2012 | Sep 2011 226.889 → Mar 2012 229.392 | 1.1% | 2.2% | — |
| Nov 2011 | Mar 2011 223.467 → Sep 2011 226.889 | 1.53% | 3.06% | — |
| May 2011 | Sep 2010 218.439 → Mar 2011 223.467 | 2.3% | 4.6% | — |
| Nov 2010 | Mar 2010 217.631 → Sep 2010 218.439 | 0.37% | 0.74% | — |
| May 2010 | Sep 2009 215.969 → Mar 2010 217.631 | 0.77% | 1.54% | — |
| Nov 2009 | Mar 2009 212.709 → Sep 2009 215.969 | 1.53% | 3.06% | — |
| May 2009 | Sep 2008 218.783 → Mar 2009 212.709 | -2.78% | -5.56% | — |
| Nov 2008 | Mar 2008 213.528 → Sep 2008 218.783 | 2.46% | 4.92% | — |
| May 2008 | Sep 2007 208.49 → Mar 2008 213.528 | 2.42% | 4.84% | — |
| Nov 2007 | Mar 2007 205.352 → Sep 2007 208.49 | 1.53% | 3.06% | — |
| May 2007 | Sep 2006 202.9 → Mar 2007 205.352 | 1.21% | 2.42% | — |
| Nov 2006 | Mar 2006 199.8 → Sep 2006 202.9 | 1.55% | 3.1% | — |
| May 2006 | Sep 2005 198.8 → Mar 2006 199.8 | 0.5% | 1% | — |
| Nov 2005 | Mar 2005 193.3 → Sep 2005 198.8 | 2.85% | 5.7% | — |
| May 2005 | Sep 2004 189.9 → Mar 2005 193.3 | 1.79% | 3.58% | — |
| Nov 2004 | Mar 2004 187.4 → Sep 2004 189.9 | 1.33% | 2.66% | — |
| May 2004 | Sep 2003 185.2 → Mar 2004 187.4 | 1.19% | 2.38% | — |
| Nov 2003 | Mar 2003 184.2 → Sep 2003 185.2 | 0.54% | 1.08% | — |
| May 2003 | Sep 2002 181 → Mar 2003 184.2 | 1.77% | 3.54% | — |
| Nov 2002 | Mar 2002 178.8 → Sep 2002 181 | 1.23% | 2.46% | — |
| May 2002 | Sep 2001 178.3 → Mar 2002 178.8 | 0.28% | 0.56% | — |
| Nov 2001 | Mar 2001 176.2 → Sep 2001 178.3 | 1.19% | 2.38% | — |
| May 2001 | Sep 2000 173.7 → Mar 2001 176.2 | 1.44% | 2.88% | — |
| Nov 2000 | Mar 2000 171.2 → Sep 2000 173.7 | 1.46% | 2.92% | — |
| May 2000 | Sep 1999 167.9 → Mar 2000 171.2 | 1.97% | 3.94% | — |
| Nov 1999 | Mar 1999 165 → Sep 1999 167.9 | 1.76% | 3.52% | — |
| May 1999 | Sep 1998 163.6 → Mar 1999 165 | 0.86% | 1.72% | — |
| Nov 1998 | Mar 1998 162.2 → Sep 1998 163.6 | 0.86% | 1.72% | — |
| Sep 1998 | Sep 1997 161.2 → Mar 1998 162.2 | 0.62% | 1.24% | — |
Sources: BLS CPI-U NSA via FRED (CPIAUCNS), TreasuryDirect's I-Bond rate formula and rate chart, the Nowflation nowcast. Projections, not promises. The COLA is set by the Social Security Administration with the September CPI; I-Bond rates by the Treasury on the first business day of November and May; tax-year amounts by the IRS in a revenue procedure each fall. The IRS indexes from statutory base-year amounts with cumulative factors and rounds once, so chaining from the published 2026 amounts can differ from the official 2027 figures by one rounding step ($25 / $50). Chained CPI-U initial values are revised. Not tax, benefits or investment advice. Every call is graded on the scoreboard after the announcement.
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