The six-month certificate is the most-shopped CD term and the least understood one, because it is the term where the competition is not another bank. At six months, the honest comparison is with the 26-week Treasury bill — a product with no early-withdrawal penalty, a $100 minimum, a weekly auction, and interest that your state cannot tax. A "best 6-month CD rates" table ranks banks against each other. This page ranks the certificate against the thing it is actually competing with.
It prints no bank's rate, for the reason set out on the hub page for this cluster: any list is a snapshot, and the number is the one thing on the page guaranteed to have moved by the time you read it. What it does instead is show you the official baseline, the after-tax arithmetic on six months, and the two features of a short certificate that the rate hides.
What the short end actually paid
The FDIC publishes national deposit rates by term each month. On the table effective 17 August 2026, the national average 6-month CD rate was 1.41%. On the same table, the 6-month Treasury yield was 3.98%. The average six-month certificate in the country paid about a third of what the government was paying for the same six months.
That gap is not evidence that CDs are a bad product. The FDIC's average is weighted by each institution's share of deposits, so it is dominated by the largest branch banks, which pay very little on certificates because they do not need to. The hub page sets out why the national average looks nothing like advertised rates and prints the full table for every term. For this page the point is simpler: the Treasury yield for six months is the number a competitive six-month certificate has to be measured against, and it is published, dated and free.
The competitor is not another bank
A Treasury bill is short-term federal debt. The 26-week bill is auctioned every week, in $100 increments from a $100 minimum, and is sold at a discount: you pay less than face value and receive face value at maturity, the difference being your interest. Two features make it the six-month CD's real rival.
There is no penalty. A bill has no early-withdrawal clause because there is no withdrawal. If you need the money before maturity you sell the bill through a brokerage, at the market price — which for a bill with a few months left is very close to what you paid, though not guaranteed to equal it. Compare that with a certificate, where leaving early costs a fixed slice of interest whatever the market is doing.
The interest is exempt from state and local income tax. Bank interest is not. In a state with an income tax this is worth roughly the state rate multiplied by the yield, and it is invisible on every comparison table because tables compare headline rates.
Two features favour the certificate. A CD's rate is locked at purchase with no auction to wait for and no brokerage account to open, and a CD is FDIC-insured while a bill is backed directly by the Treasury — a different guarantee, both federal, covered on the insurance page so that the difference is stated properly rather than glossed.
The after-tax arithmetic on six months
$10,000 for six months. The rates are illustrative — deliberately set close together and close to where the market sat at the time of writing — and the saver pays an illustrative 24% federal rate and lives in a 6% income-tax state.
| Headline (illustrative) | Gross, six months | Taxed at | After tax | |
|---|---|---|---|---|
| 6-month CD | 4.00% | $200.00 | 30% (federal + state) | $140.00 |
| 26-week T-bill | 3.90% | $195.00 | 24% (federal only) | $148.20 |
The bill wins with the lower headline. The state exemption on a 3.90% yield in a 6% state is worth about 0.23 percentage points, so as a rule of thumb a six-month certificate has to beat the 26-week bill by roughly a quarter of a point to come out ahead in a state at that tax rate, and by more in a higher-tax state. In a state with no income tax the exemption is worth nothing and the certificate wins the table as printed. The general version of this arithmetic, with the one-year comparison, is on HYSA vs CD vs T-bills.
On $10,000 the difference is eight dollars. On $100,000 it is eighty. Whether that is worth a brokerage account is a personal question; whether it is worth knowing is not.
The penalty bites hardest at six months
Every fixed-term certificate carries an early-withdrawal penalty, and its size is set by the bank, not the term. Published schedules at three large online banks in September 2026 charged 60 to 90 days' interest for withdrawing early from a six-month certificate. Six months is about 182 days. So the penalty for leaving a six-month CD early is between a third and a half of everything it would have earned in its entire life — a far larger share than the same 60 or 90 days represents on a two- or three-year certificate.
The legal floor is much lower than that. Regulation D requires only that a time deposit carry a penalty of at least seven days' simple interest on money withdrawn in the first six days. Everything above that floor is the institution's choice, disclosed in the account terms under Truth in Savings, and it varies more between banks than the rates do. The penalty page prices this properly across terms.
The practical consequence is that a six-month certificate is the wrong home for money you might need in month four. If there is real uncertainty about the date, the honest alternatives are a savings account, a Treasury bill, or a no-penalty CD — which gives up some rate in exchange for an exit, and whose economics only make sense once you have seen what the exit on a standard certificate costs.
Specials, and the term after the term
The short end is where banks advertise. A 7-month or 9-month "special" at an attractive rate is how an institution puts a high number in the comparison tables without repricing its whole ladder, and the number is genuine for the seven or nine months.
What happens afterwards is the part to read. Most certificates renew automatically at maturity — into a standard term, at whatever rate the bank is offering that day, which is rarely the special. For certificates of one year or less, Truth in Savings requires only the lighter form of advance notice before maturity, and the grace period in which you can withdraw without penalty is short: around ten to fourteen days at the institutions whose schedules were checked for this page. Miss it and the special has quietly become an ordinary certificate at an ordinary rate for another term you did not choose.
Put the maturity date in your own calendar, two weeks early. That one habit is worth more than the difference between the top two rates in any table.
Six months versus a year
Two six-month certificates back to back, or one twelve-month? The FDIC average paid 0.30 points more for twelve months than for six on the August 2026 table (1.71% against 1.41%). Whether the year is worth it depends on something nobody knows: where rates are in six months. If they fall, the twelve-month certificate was right; if they rise, the pair of six-month certificates was. The rate table cannot settle it and neither can a forecast.
What settles it is the date. If the money is needed in six months, the six-month certificate is correct and the question does not arise. If it is needed in a year, the one-year page covers what the longer lock gives up. And if the honest answer is "somewhere between", the standard way to stop guessing is a ladder — staggered maturities so that some money is always a few months from free, at the cost of a little yield on the short rungs.
What six-month money is for
The six-month certificate has a narrow and useful job: money with a known date about six months out. Property tax due in the spring. A tuition instalment. An insurance premium paid annually. The kind of expenses that belong in sinking funds, where the amount and the date are both known and the only question is where the money sits until then.
It is not for emergency money, which has no date and whose job is availability — where to keep an emergency fund covers that. And it is a poor fit for a house down payment with a closing date that might move, because closing dates move and the penalty does not care why.
What to actually do
Check the date first. If the money is not needed on a specific date roughly six months out, a six-month certificate is the wrong shape and the rate is beside the point.
Measure the offer against the 26-week Treasury yield, not against other banks. The FDIC's monthly table prints both the national CD average and the Treasury yield for the term. A competitive six-month certificate is one that clears the bill after your state tax — about a quarter of a point above it in a 6% state, more in a higher-tax one.
Read the penalty before the rate. At six months the penalty is a third to a half of the total interest at the institutions checked. Between two certificates a tenth of a point apart, the milder penalty wins.
Read the APY, not the interest rate, and read which balance it applies to — APR vs APY explains why only the APY is comparable.
Decide the renewal now. Set the certificate to pay out at maturity if the money has a destination, or write the maturity date in your own calendar two weeks early if it does not. Do not leave the decision to a ten-day grace period you will not notice.
If the date is uncertain, do not buy a fixed-term certificate at all. A Treasury bill, a savings account or a no-penalty CD are all better fits for money that might move, and each costs less than a 90-day penalty on a six-month term.
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