The I bond rate resets November 1: half of it is already known
U.S. Series I savings bonds get a new rate every May 1 and November 1. The next reset is November 1, 2026. The fixed half of the rate is a Treasury decision nobody outside it can see yet. The inflation half is different: it is set by a published government index, and every number it needs is already out. This post walks through the arithmetic and how the rate is built. It is an explainer of the mechanics, not a recommendation to buy or avoid anything.
What the rate is made of
An I bond’s composite rate combines two pieces:
- A fixed rate, set at issue and unchanged for the bond’s life of up to 30 years.
- A semiannual inflation rate, reset every six months, based on the change in the non-seasonally adjusted CPI-U (all items, including food and energy).
TreasuryDirect gives the formula as: fixed rate + (2 × semiannual inflation rate) + (fixed rate × semiannual inflation rate). The inflation rate is doubled because it covers six months and the composite is quoted as an annual rate.
The current numbers, for bonds issued May through October 2026, are a 0.90% fixed rate and a 1.67% semiannual inflation rate, which produce a 4.26% composite. TreasuryDirect says the 1.67% is the CPI-U change from 324.8 in September 2025 to 330.213 in March 2026.
The November inflation number, worked out
The November reset uses the six months from March to September. Both index levels have been published by the Bureau of Labor Statistics:
| Index | CPI-U (NSA, 1982–84 = 100) |
|---|---|
| March 2026 | 330.213 |
| September 2026 | 336.940 |
| Change | 6.727 points, or about 2.04% |
So the semiannual inflation rate for the November reset works out to roughly 2.04%, up from 1.67%. That is our own arithmetic from BLS data using the method TreasuryDirect describes in its past announcements; the official figure is whatever Treasury publishes.
For comparison, the previous November reset used 319.799 (March 2025) and 324.8 (September 2025): a 1.56% semiannual rate.
What the composite could look like
Because the inflation half is effectively known, the composite depends mostly on the unknown fixed rate. The table plugs a few illustrative fixed rates into the published formula with a 2.04% inflation rate. These are not forecasts of what Treasury will set.
| Fixed rate | Composite (approx.) |
|---|---|
| 0.00% | 4.08% |
| 0.50% | 4.59% |
| 0.90% (same as now) | 5.00% |
| 1.30% | 5.41% |
The fixed rate matters beyond the first six months, because it stays with a bond for as long as it is held. TreasuryDirect’s history table shows how much it moves:
| Issue period | Fixed rate |
|---|---|
| May 2022 – Oct 2022 | 0.00% |
| Nov 2022 – Apr 2023 | 0.40% |
| May 2023 – Oct 2023 | 0.90% |
| Nov 2023 – Apr 2024 | 1.30% |
| Nov 2024 – Apr 2025 | 1.20% |
| May 2025 – Oct 2025 | 1.10% |
| Nov 2025 – Apr 2026 | 0.90% |
| May 2026 – Oct 2026 | 0.90% |
The fixed rate has ranged from 0.00% to 1.30% in this window, so the number Treasury picks on November 1 could land anywhere in or beyond that range.
Why the issue month matters
A bond’s rate does not change on November 1 for everyone. Each bond’s inflation component resets every six months from its own issue month. A bond bought in October 2026 keeps its 4.26% composite through March 2027, then moves to whatever composite applies after that. A bond bought in November 2026 gets the new composite for its first six months. Only the fixed rate is locked at purchase: a bond bought in October keeps 0.90% for life, one bought in November gets the new fixed rate for life.
That is the real trade-off behind the “buy before or after November 1” question people ask each cycle. In the near term the inflation half is already known, so the choice hinges mostly on the unknown fixed rate. For a holding period of many years, the fixed rate matters most; for a short hold, the six-month inflation reset does.
The rules that shape how an I bond fits a plan
- Purchase limit: TreasuryDirect lists $10,000 in electronic I bonds per Social Security number or EIN per calendar year. Paper I bonds are no longer sold, as of January 1, 2025.
- Minimum hold: bonds can’t be cashed for 12 months.
- Early-redemption cost: cashing before five years forfeits the last three months of interest.
- Compounding: interest accrues monthly and compounds semiannually.
- Deflation: the bond’s value does not decline if CPI-U falls.
- Taxes: federal income tax applies; state and local income tax does not. Holders can report the interest yearly or defer it until the bond is cashed. Interest used for qualified higher education expenses may be excluded under conditions described on TreasuryDirect.
Where this fits in a retirement or budget projection
An I bond is an inflation-linked, low-volatility holding, so it sits in the same conversation as the “cash and fixed income” return assumptions in any plan. Our guide on return assumptions for retirement projections explains why the number you plug in for safe assets matters as much as the one for stocks. If you are weighing savings against a loan, the guides on debt payoff vs investing and paying down a mortgage vs investing show the comparison as a rate-versus-rate question.
Two practical points when modelling an I bond:
- Model the real return, not the headline. The composite rate already contains inflation. The part that stays above inflation is mostly the fixed rate, which is why it is the number to watch.
- Treat the annual limit and the 12-month lock as constraints. They cap how much of a plan this holding can represent, and they keep it out of an emergency fund’s first year.
You can test how a different assumed return on your safe assets changes a projection in the USA retirement calculator, or compare a loan’s rate to a savings rate in the debt payoff calculator.
What to check on November 1
When Treasury publishes, compare three things against the numbers above: the new fixed rate, the semiannual inflation rate (our arithmetic says about 2.04%), and the resulting composite. Then check TreasuryDirect’s rates page for any change to purchase limits or redemption rules before relying on this post’s descriptions.
This article is educational and not financial advice. Rates, limits and rules are set by the U.S. Treasury and can change; confirm them on TreasuryDirect.gov before acting.