Series I Bonds Rate November 2026 Prediction: 5.41%

After spiking to 40 year highs in 2021 and 2022 because of the pandemic, inflation had been settling down a bit the last few years. Unfortunately, as a result of the Iran war and its impact on the price of oil (which is integrated into practically everything we buy), inflation has begun rearing its ugly head again.

As a result, the Fed is unlikely to be lowering rates anytime soon. If anything, they’re holding pat or going up slightly.

Higher rates are bad if you’re a borrower, but they’re great if you’re a saver.

With the latest inflation rates, we can now calculate what we think Series I bond rates will be when they reset in November.

First, if you’re wondering how Series I bonds work, we explain it all after the rate calculation. We start with what the rate is expected to be when it adjusts in November followed by how Series I bonds work:

🔃 Updated October 2026 with the predicted Series I Savings bond rates for November 2026 now that latest inflation data has been published. The predicted rate for the bonds sold in November will be 5.41% for the first 6 months. Also, you will need an ID.me account to access TreasuryDirect after 10/28/26.

💸 November 2026 Interest Rate Prediction: 5.41%

With the September inflation figures out from the BLS, we can now predict what the inflation rate will be for Series I bonds issued November 2026 through April 2027.

With the March 2026 CPI-U of 330.213 and a September 2026 CPI-U of 336.940, we have a semi-annual inflation rate of 2.04%, which means the inflation-adjusted variable rate will be 4.08% – up from 3.34%.

We won’t know what the fixed portion will be until Treasury announces it on November 1st, but as we’ve learned from reading Tipswatch, it tends to track with the 5-year TIPS. Take the average real yield of the 5-year TIPS over the preceding six months and multiply by 0.65. With 5-year real yields averaging right around 2%, that gives us 1.30% – a big jump from 0.90% – and it’s close enough to the line that 1.40% is possible.

If we assume a fixed rate of 1.30%, the composite rate would be 5.41%. If it comes in at 1.40%, the composite rate would be 5.51%.

As always, you can peek at EyeBonds.info to see how the inflation rate changes impact your specific bonds based on its fixed rate.

Should you buy in October? If you buy before November 2026, you get the fixed rate of 0.90% while earning the May-October 2026 variable rate of 3.34% – this means you will be earning at the 4.26% annual rate for six months. Then, after six months, your variable rate will increase to 4.08% and you’ll earn 5.00%. If you wait until November, you’ll earn about 5.41% for the first six months and, more importantly, lock in a fixed rate that’s likely 0.40% higher for the life of the bond. Unless something unexpected happens, waiting until November is the better move – and either way, the purchase counts toward your 2026 limit.

💸 May 2026 Interest Rate: 4.26%

✅ The math is outlined in the prediction below but now that May 1st has come and gone, we know the fixed rate of bonds will be 0.90% so the composite rate is confirmed to be 4.26% for the first six months.

With the latest inflation figures out for March from the BLS, we can now predict what the inflation rate will be for Series I bonds issued May 2026 through October 2026.

With the September 2025 CPI-U of 324.800 and a March 2026 CPI-U of 330.213, we have a semi-annual inflation rate of 1.67%, which means the inflation-adjusted variable rate will be 3.34%.

We won’t know what the fixed portion will be but as we’ve learned from reading Tipswatch, it tends to track with the 5-year TIPS. Take the average real yield of the 5-year TIPS over the preceding six months and multiply by 0.65 – which gives us 0.90%.

If we assume a fixed rate of 0.90%, the composite rate would be 4.26%.

As always, you can peek at EyeBonds.info to see how the inflation rate changes impact your specific bonds based on its fixed rate.

Should you buy in April? If you buy before May 2026, you get the fixed rate of 0.90% while earning the November 2025-April 2026 variable rate of 3.12% – this means you will earn at the 4.16% annual rate for six months. Then, after six months, your variable rate will increase to 3.34% and you’ll get 4.26%.

Remember the restrictions on a Series I bond – you can’t redeem it within a year and if you redeem it within 5 years, you have to surrender the last three months of interest. The interest is not subject to state and local taxes though.

What Are Series I Bonds?

Series I Bonds are bonds issued by the United States Treasury that accrue interest for thirty years. That interest income is taxable at the federal level but they are tax free at the state and local level.

The interest rate is adjusted twice a year and is based, in part, on inflation (more on that later).

Each person is allowed to buy up to $10,000 in Series I bonds each year, electronically through TreasuryDirect.gov.

Here are step by step instructions on how to buy any Treasury bond or bill.

Tax Considerations

The best part about Series I bonds is that the interest is only taxable at the federal level. Interest is tax free at the state and local level.

While your interest continues to accrue every month, it is only added to the principal every six months. You can elect to report the interest every year, but most people (as TreasuryDirect advises) report it when they cash in the bond. When you cash in your bond, you’ll get a Form 1099-INT.

If you use the interest to pay for higher education expenses, that interest may be excluded from your taxes too.

Finally, you cannot cash in the bond within a year of purchasing it. If you cash it within five years of purchasing it, you lose the previous three months of interest.

How Are Interest Rates Calculated?

The interest rate of the Series I bond has two components – a fixed rate and an inflation-adjusted rate.

The fixed rate is set for the life of the bond when you buy it. The fixed rate is announced in May and November.

The inflation adjusted rate depends on the CPI-U, which is an inflation figure released every month by the U.S. Bureau of Labor Statistics. This is the number everyone refers to when talking about inflation, it’s the Consumer Price Index for all Urban Consumers (hence the -U).

The inflation adjusted rate is set twice a year, in May and November, based on CPI-U data released in April and October. In April, you get inflation from the prior October through March. With that information, you can determine the inflation adjusted rate.

The well-known equation is:

Composite interest rate = Fixed rate + (2 * Semiannual inflation rate) + (Semiannual inflation rate * Fixed rate)

When you buy a bond, you get the inflation adjusted rate at the time of purchase for six months. Then it adjusts to the new rate.

If you purchase a bond in April 2023, you get the rate that was set in November 2022 for six months. Then, you get the rate announced in May 2023 for six months.

One final note on the rate, the inflation rate can be negative but the interest rate on the bonds won’t be negative. It just gets set to zero.

Interest Compounds Semiannually

The interest on the Series I Bond compounds semiannually, or every six months, based on the issue date of the bond.

So if you buy a bond today, you will earn the interest rate based on how much you purchased. Then, in six months, all that accrued interest is added to the principal of the bond. For the next six months, you earn interest based on the higher amount. And so on.

How To Predict Series I Bond Interest Rates

How are all these experts able to predict the interest rates of future bonds? It’s because the rates are based on inflation and inflation figures are released every month.

You can use the equation above to calculate exactly what the bond will be if you make assumptions about the fixed rate. The fixed rate is announced at the same time and the only part of the equation that is a “guess.” You can simply guess it’s 0% and smile at the bonus if it’s higher.

When Should You Buy Series I Bonds?

Whenever you want!

The best times to buy the bond is near the end of the month because you get “credit” for that entire month. If you buy it on April 20th, you get all the interest you would’ve accrued for the month of April. It’s a minor bit of optimization but worth noting.

If you plan to buy and don’t yet have a TreasuryDirect account, get on it because it’s an old system and it can take a while!

When Should You Sell Series I Bonds?

Given the increase in the fixed rate component, you may be wondering what you should do with existing I Bonds. First, if you don’t know what the fixed rate component of your I bonds is (but you know when you bought them), you can look it up quickly on eyebonds.info. Or you can log into TreasuryDirect and look it up there.

Recall, the fixed rate stays with a bond for its entire 30-year life, so your decision is really on whether it’s “worth it” to sell older lower fixed rate bonds for these new ones. Starting in November, an I bond with a 0% fixed rate will earn 4.08% while a new bond will earn 5.41% (if our 1.30% fixed rate prediction is accurate). That 1.30% gap repeats every six months for as long as you hold.

If you have bonds with a 0% fixed rate (bought May 2020 through October 2022) or 0.40% (November 2022 through April 2023), it may make sense to cash them out and buy new ones. Before you do, keep these in mind:

• 12-month minimum – You can’t redeem an I bond until you’ve held it for 12 months. So if you buy new ones, you’re resetting that 12-month cash out restriction.
• 3-month interest penalty – Redeem before 5 years and you forfeit the last 3 months of interest. Bonds bought in 2021 or earlier are past that window. Again, with new bonds you’re reseting that clock again.
• $10,000 annual purchase limit – Selling $30,000 of old bonds doesn’t let you buy $30,000 of new ones. You can only swap as much as your yearly limit allows.
• Taxes come due – Redeeming triggers federal income tax on all the interest that’s been accruing (it’s still exempt from state and local tax). If you’ve been deferring for years, that could be a big chunk of income on one return.
• Sell early in the month – Interest is credited on the first of each month and you don’t get credit for a partial month. Sell on the 2nd, not the 28th.

Since timing matters on both ends, the ideal swap is to redeem your old bonds in the first few days of a month and buy the new ones near the end of the month. Just wait until Treasury announces the actual fixed rate on November 1st before doing anything – if it comes in lower than expected, the math changes.

Finally, if you need the cash for something else, your lowest fixed rate bonds are the first ones you should sell.

What about TIPS?

You may have noticed that the fixed rate we predict is based on 65% of TIPS, which means TIPS are an attractive option now. You may wish to cash out old I Bonds for TIPS and here’s how to think about that decision.

Right now, a 5-year TIPS yields around 2% above inflation, compared to the 1.30% fixed rate we expect on new I bonds. TIPS pay more, but they come with a few strings attached:

The tax treatment is the big difference. With TIPS, the inflation adjustment to your principal is taxed as income every year even though you don’t get that money until the bond matures. That’s “phantom income” and it eats into the yield advantage in a taxable account. In an IRA, you defer this.

If you have less than $10,000 in old I bonds, swapping into new I bonds is the simpler move. You keep the tax deferral and you never have to worry about price swings. The extra yield from TIPS is about 0.70% – roughly $70 a year on $10,000.

If you have more than $10,000 in old I bonds, TIPS can make a lot more sense. At $10,000 a year, it could take several years to swap everything into new I bonds, and in the meantime your 0% fixed rate bonds are only keeping pace with inflation. With TIPS, you can move it all at once. A reasonable approach is to put $10,000 into new I bonds this year and the rest into TIPS.

Either way, remember that redeeming your old I bonds makes all of that accrued interest taxable in the year you cash out. If you’re sitting on a lot of interest, you may want to spread the redemptions across a couple of tax years. Be sure to talk to a tax professional who knows your situation to sort this out.

Finally, it’s better to buy individual TIPS and hold them to maturity rather than a TIPS fund. A TIPS bond held to maturity locks in that ~2% real yield. A fund never matures, so you get whatever the market price is when you sell. When rates jumped in 2022, the iShares TIPS Bond ETF (TIP) lost about 12%. Short-term TIPS funds swing less but also pay less.