I bond rate November 2026: the inflation part is 2.04%; Treasury adds the fixed rate Nov. 2
I bonds bought from May 1 through Oct. 31, 2026 earn 4.26% for their first six months: a 0.90% fixed rate plus a 1.67% semiannual inflation rate. The rate for bonds bought from Nov. 1 has two parts. Treasury sets a new fixed rate, and the inflation part is the change in the consumer price index (CPI-U, not seasonally adjusted) from March to September 2026. The Bureau of Labor Statistics published September's index on Oct. 14, 2026: 336.940, against 330.213 in March. That makes the inflation part 2.04%. Treasury announces the new fixed rate on Nov. 2.
- Bought by Oct. 31: 4.26% for six months (0.90% fixed + 1.67% inflation, doubled for a year), then the November rate for a 0.90% fixed rate.
- Bonds you already own: from their next six-month period that starts November 2026 through April 2027, each earns its own fixed rate plus the 2.04% inflation part. With a 0.90% fixed rate that is 5.00%; with a 0.00% fixed rate, 4.08%. Your bond's rate is in the table by purchase date.
- The new fixed rate is Treasury's decision; the regulation gives no formula. It stays with a bond for its 30 years.
- Cashed after 12 months, the earliest allowed, an October bond keeps nine months of interest. $10,000 grows to $10,340.00 (3.40%). A 52-week Treasury bill yielded 4.54% on September 30, 2026. Neither is taxed by states or cities.
Until Nov. 2: the new fixed rate
Both calculators below use these. The November inflation part is set at 2.04%; only the fixed rate for bonds bought from Nov. 1 is still unknown. Leave it at 0.90% to see the case where it stays the same.
Your I bond: its value now and its next rate
Buying now: October or November I bond vs a 52-week T-bill vs savings, after tax
Result
| Option | Value at the end, before tax | Return a year, before tax | After tax, a year | Federal tax | State and city tax |
|---|
| Six-month period from | October bond | November bond |
|---|
How the November 2026 rate is set
The rate for new bonds is the fixed rate plus twice the six-month inflation rate plus the two multiplied together, rounded to the nearest hundredth of a percent (31 CFR 359.14). For May 2026 the inflation part was the CPI-U change from September 2025 (324.800) to March 2026 (330.213): 1.67%. With the 0.90% fixed rate that gives 0.90% + 2 × 1.67% + 0.90% × 1.67% = 4.25503%, rounded to 4.26%. November uses March 2026 (330.213) and September 2026 (336.940): (336.940 − 330.213) ÷ 330.213, rounded to the nearest hundredth, is 2.04%.
On the fixed rate the regulation says only: “The Secretary, or the Secretary's designee, determines the fixed rate of return.” On the date: “If the regularly scheduled date for the announcement is a day when the Treasury is not open for business, then the Secretary will make the announcement on the next business day”. Nov. 1, 2026 is a Sunday. Treasury's data page shows “New Data Expected 11/02/2026”, and the rule adds that “the effective date of the rates remains the first day of the month of the announcement”.
| Fixed rate | Rate for six months with the 2.04% inflation part |
|---|---|
| 0.00% | 4.08% |
| 0.50% | 4.59% |
| 0.90% | 5.00% |
| 1.10% | 5.20% |
| 1.30% | 5.41% |
| 1.50% | 5.61% |
October or November: the 12-month case
An October bond's first six months are fixed at 4.26%; a November bond starts at the new fixed rate plus the November inflation part, and keeps that fixed rate for its whole life. Cashed at 12 months, each keeps nine months of interest: “If you redeem a bond less than five years after the issue date, we will reduce the overall earning period by three months.” On $10,000:
| Bond | First six months | Value after 12 months | Return for the year |
|---|---|---|---|
| October bond, 0.90% fixed rate | 4.26% | $10,340.00 | 3.40% |
| November bond, 0.90% fixed rate | 5.00% | $10,380.00 | 3.80% |
| November bond, 1.10% fixed rate | 5.20% | $10,392.00 | 3.92% |
| November bond, 1.30% fixed rate | 5.41% | $10,412.00 | 4.12% |
| November bond, 1.50% fixed rate | 5.61% | $10,424.00 | 4.24% |
| 52-week Treasury bill at 4.54% | – | $10,452.76 | 4.54% |
To get the October terms, the bond has to be issued in October. For electronic bonds, “The issue date of a book-entry Series I savings bond is the first day of the month in which the security posts to the current holdings of the account owner.” Oct. 31, 2026 is a Saturday. Purchases are made online at TreasuryDirect; the rule says “You may only purchase book-entry Series I savings bonds online through your New Treasury Direct account.”
Fixed rates by purchase date, and the next rate
Your bond's fixed rate depends on when you bought it and never changes. Its next six-month rate, which starts in the month of your purchase anniversary or six months after it (November 2026 through April 2027), is that fixed rate plus the November inflation part.
| Bought | Fixed rate | Next six-month rate (2.04% inflation part) |
|---|---|---|
| Nov. 2025 – Oct. 2026 | 0.90% | 5.00% |
| May 2025 – Oct. 2025 | 1.10% | 5.20% |
| Nov. 2024 – April 2025 | 1.20% | 5.30% |
| Nov. 2023 – Oct. 2024 | 1.30% | 5.41% |
| May 2023 – Oct. 2023 | 0.90% | 5.00% |
| Nov. 2022 – April 2023 | 0.40% | 4.49% |
| May 2020 – Oct. 2022 | 0.00% | 4.08% |
| Nov. 2019 – April 2020 | 0.20% | 4.28% |
| Nov. 2018 – Oct. 2019 | 0.50% | 4.59% |
| May 2018 – Oct. 2018 | 0.30% | 4.39% |
| Nov. 2017 – April 2018 | 0.10% | 4.18% |
| Nov. 2016 – Oct. 2017 | 0.00% | 4.08% |
| Nov. 2015 – Oct. 2016 | 0.10% | 4.18% |
| Nov. 2014 – Oct. 2015 | 0.00% | 4.08% |
| May 2014 – Oct. 2014 | 0.10% | 4.18% |
| Nov. 2013 – April 2014 | 0.20% | 4.28% |
| Nov. 2010 – Oct. 2013 | 0.00% | 4.08% |
| May 2010 – Oct. 2010 | 0.20% | 4.28% |
| Nov. 2009 – April 2010 | 0.30% | 4.39% |
| May 2009 – Oct. 2009 | 0.10% | 4.18% |
| Nov. 2008 – April 2009 | 0.70% | 4.79% |
| May 2008 – Oct. 2008 | 0.00% | 4.08% |
| Nov. 2007 – April 2008 | 1.20% | 5.30% |
| May 2007 – Oct. 2007 | 1.30% | 5.41% |
| May 2006 – April 2007 | 1.40% | 5.51% |
| Nov. 2005 – April 2006 | 1.00% | 5.10% |
| May 2005 – Oct. 2005 | 1.20% | 5.30% |
| May 2004 – April 2005 | 1.00% | 5.10% |
| May 2003 – April 2004 | 1.10% | 5.20% |
| Nov. 2002 – April 2003 | 1.60% | 5.71% |
| Nov. 2001 – Oct. 2002 | 2.00% | 6.12% |
| May 2001 – Oct. 2001 | 3.00% | 7.14% |
| Nov. 2000 – April 2001 | 3.40% | 7.55% |
| May 2000 – Oct. 2000 | 3.60% | 7.75% |
| Nov. 1999 – April 2000 | 3.40% | 7.55% |
| Nov. 1998 – Oct. 1999 | 3.30% | 7.45% |
| Sept. 1998 – Oct. 1998 | 3.40% | 7.55% |
I bond vs T-bill: the rules side by side
| I bond | Treasury bill | |
|---|---|---|
| State and local income tax | “Interest on U.S. savings bonds is exempt from state and local taxes.” | “Interest income from Treasury bills, notes, and bonds is subject to federal income tax but is exempt from all state and local income taxes.” |
| Federal income tax, when | When you cash it, unless you choose to report it each year: “Postpone reporting the interest until the earlier of the year you cash or dispose of the bonds or the year in which they mature.” | “Generally, you report this interest income when the bill is paid at maturity.” |
| Term | 30 years; it earns interest until you cash it | “These bills generally have a 4-, 8-, 13-, 26-, or 52-week maturity period.” |
| Rate | Fixed rate for life plus an inflation part reset every six months | Set by the price you pay; “They are generally issued at a discount” |
| Cashing early | Not in the first 12 months; before 5 years, the last three months of interest are lost | Matures in weeks |
| Limit | “limited to $10,000 for Series EE savings bonds and $10,000 for Series I savings bonds” a calendar year | – |
| College costs | Interest can be excluded from federal income if you pay qualified higher education expenses the same year and meet other conditions (Education Savings Bond Program) | – |
How the calculators work
- I bond values. Treasury values a $25 unit and scales it to your amount (31 CFR 359.19 and 359.55). Within each six-month period the unit grows by (1 + rate ÷ 2) raised to the months elapsed ÷ 6, rounded to the cent every month (359.39). Before five years the value is the one three months earlier (359.7). Our code reproduces all 57,609 values in Treasury's Savings Bonds Value Files for Series I, every purchase month from September 1998 through the Nov. 2026 table, to the cent.
- November's inflation part is the published change in CPI-U from March to September 2026, rounded to the nearest hundredth (359.11): 2.04%.
- The 52-week bill is compounded at its coupon-equivalent yield; for holds past a year it is assumed to roll over at the same yield. Savings earn the APY you enter.
- Taxes. A year of interest at each option's yearly rate goes through 2026 federal and state rules, the 3.8% net investment income tax, and New York City or Yonkers tax, with the I bond and bill interest exempt from state tax. These are the engines of our cash yield after tax calculator. The timing of tax is not modeled: I bond interest is usually taxed when you cash the bond.
What the calculators leave out
- Paper I bonds bought with a tax refund, and bonds bought as gifts or in trusts.
- The Education Savings Bond Program exclusion and its income limits (IRS Form 8815).
- Selling a Treasury bill before it matures, and T-bill ETFs and money funds (see the cash yield calculator).
Numbers used, with sources
- I bond rates, September 1998 to October 2026: Treasury FiscalData, I Bonds Interest Rates (Bureau of the Fiscal Service). Current: 0.90% fixed, 1.67% inflation, 4.26% for bonds bought May 2026 to Oct. 2026.
- Values checked against: Treasury FiscalData, Savings Bonds Value Files (57,609 values).
- CPI-U, not seasonally adjusted: September 2025 324.800 (BLS release for September 2025, Table 1); March 2026 330.213 (BLS release for March 2026, Table 1); July 2026 333.918 and August 2026 334.980 (BLS release for August 2026, Table 1); September 2026 336.940 (BLS release for September 2026, Table 1). The March and July levels equal Treasury's reference CPI for June 1 and Oct. 1, 2026, and Treasury's reference CPI for Nov. 30, 2026 matches August and September (Treasury FiscalData, TIPS and CPI Data (reference CPI)).
- Release date of the September 2026 CPI (Oct. 14, 2026): BLS, Schedule of Releases for the Consumer Price Index.
- Treasury bill yields on September 30, 2026: 52-week 4.54%, 26-week 4.34% (Treasury, Daily Treasury Bill Rates).
- Rules: 31 CFR Part 359, Offering of United States Savings Bonds, Series I (eCFR); 31 CFR 363.52, annual purchase limit (eCFR); IRS Publication 550 (2025), Investment Income and Expenses.
Treasury's data page describes the bonds this way: “I bonds earn interest until the first of these events: You cash in the bond or the bond reaches 30 years old.” and “Please note that there is a three-month interest penalty for an I bond that is redeemed within five years from issuance.”
Test cases
A separate reference implementation computed 225 comparisons (all 50 states and DC, both filing statuses, holds of 12 months to 5 years, several fixed rates) and 679 bond lookups (every purchase month since September 1998). This page's code agrees with it to the cent. The self-test reruns the comparison in your browser.
Rechecks and changes
We will update the page on Nov. 2, 2026, when Treasury announces the fixed rate for new bonds.
- . The Bureau of Labor Statistics published the September 2026 CPI-U on Oct. 14: 336.940. The November inflation part is therefore 2.04% (from 330.213 in March), and the September input is gone. Only the fixed rate for new bonds, which Treasury announces Nov. 2, is still an assumption.
- . First published, before the September CPI and the November announcement.
Dollars Ahead is not affiliated with the U.S. Treasury, TreasuryDirect or the Bureau of Labor Statistics. This tool shows what published rules do to the numbers you enter. It is not financial or tax advice. Your TreasuryDirect account shows your bonds' official values.