A Treasury bill (T-Bill) is a short-term U.S. government security that matures in one year or less. Sold at a discount to face value, T-Bills deliver your return at maturity rather than through periodic interest payments. This calculator converts between purchase price and discount rate, shows yield comparisons across all maturities, builds a T-Bill ladder, and compares T-Bill after-tax yield against savings alternatives.
T-Bill Details
Minimum $100, in multiples of $100
Amount you pay at purchase (less than face value)
Bank discount rate from auction or secondary market
T-Bills are exempt from state and local taxes
Return Breakdown
Yield Comparison Across Maturities
Investment yield (BEY) at each standard T-Bill maturity using your discount rate:
T-Bill vs Savings Account Comparison
For informational purposes only. Not financial or tax advice. Verify rates at TreasuryDirect.gov before investing.
T-Bill Ladder Calculator
Spread your investment across multiple T-Bill maturities for regular reinvestment opportunities.
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Recent T-Bill Auction Reference Rates
Rates shown are approximate examples for reference only. Check TreasuryDirect.gov for current auction results.
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How to Use the T-Bill Calculator
Treasury bills are among the safest investments available, backed by the full faith and credit of the U.S. government. This T-Bill calculator handles everything from basic yield math to yield comparisons across maturities, T-Bill ladder planning, and after-tax comparisons with savings alternatives.
Step 1: Enter Face Value, Maturity, and Rate
Enter the face value you want to purchase (minimum $100, in $100 increments). Select your T-Bill term — the 13-week (91-day) bill is the most commonly purchased. Then choose your input method: enter a purchase price if you know what you paid, or a discount rate if you're checking an auction result. A $10,000 face-value 13-week T-Bill at a 4.35% discount rate costs about $9,890.29, earning you $109.71 at maturity.
Step 2: Understanding Discount vs Investment Yield
The discount yield (bank discount rate) is how T-Bills are quoted at auction — it expresses the return as a percentage of face value on a 360-day basis. The bond equivalent yield (BEY) is more useful for comparisons because it expresses the return as a percentage of your actual investment cost on a 365-day basis, making it directly comparable to APYs on savings accounts and CDs.
Step 3: Compare Yields Across Maturities
The yield comparison chart shows the investment yield at all five standard T-Bill maturities (4-week, 8-week, 13-week, 26-week, 52-week) using your discount rate. This helps you decide whether to lock in a longer-term T-Bill or roll a shorter-term one. In normal markets, longer T-Bills yield slightly more; in inverted yield curve environments, shorter ones yield more.
Step 4: Build a T-Bill Ladder
A T-Bill ladder splits your investment across multiple maturities — for example, $50,000 across four rungs means $12,500 each in 4-week, 8-week, 13-week, and 52-week T-Bills. As each rung matures, you reinvest it at current rates. This strategy provides regular liquidity, averages out rate changes over time, and avoids being locked into any single maturity date. Use the ladder calculator to see projected returns for each rung.
Step 5: T-Bill vs HYSA Comparison
T-Bills are exempt from state income tax — a key advantage in high-tax states. Enter your HYSA/CD rate and state tax rate to see the break-even comparison. For example, in California (13.3% top rate), a T-Bill yielding 4.35% is equivalent to a savings account paying 5.01%. In a no-state-tax state like Florida or Texas, the advantage shrinks to the federal-only calculation.
T-Bill Rates in 2026
As of March 2026, Treasury bill yields have been in the 4.10%–4.35% range across maturities. The 4-week T-bill has been yielding approximately 4.25%, the 13-week (3-month) bill around 4.30%, and the 52-week bill approximately 4.10%. The yield curve for T-Bills has been slightly inverted at the short end, with shorter-term bills yielding slightly more than the 52-week, reflecting market expectations about the Federal Reserve's rate trajectory.
Rates approximate as of March 2026, change weekly at Treasury auctions. Verify current rates at TreasuryDirect.gov before investing.
T-Bills vs HYSA: Which Is Better?
The answer depends on your state tax rate. Consider $10,000 invested for one year: at a 4.25% T-Bill yield, you earn $425 in interest — and that $425 is entirely exempt from state income taxes. The same $10,000 in a 4.50% HYSA earns $450, but every dollar is taxable at the federal and state level. In a state with a 5% income tax, the after-tax yield on the HYSA drops to approximately 4.28% — almost identical to the T-Bill. In a state with a 9% income tax (California, New York high brackets), the HYSA's effective yield drops to about 4.10%, making the 4.25% T-Bill the clear winner despite a lower nominal rate.
In states with no income tax (Florida, Texas, Nevada, Washington, Wyoming, South Dakota, Tennessee), T-Bills lose their key advantage and the comparison becomes purely nominal rate vs. nominal rate.
How to Buy T-Bills on TreasuryDirect
TreasuryDirect.gov is the U.S. Treasury's direct purchase portal — no broker, no fees, no middlemen. To get started: create a TreasuryDirect account (takes about 10 minutes), link your bank account for ACH transfers, and then navigate to "BuyDirect" to purchase T-Bills at the next scheduled auction. 4-week bills auction weekly on Tuesdays; 13-week and 26-week bills auction on Mondays; 52-week bills auction every four weeks. You bid "non-competitive," which guarantees you'll receive the auction's clearing rate. Minimum purchase is $100. At maturity, the full face value is automatically deposited back to your linked bank account.
Alternatively, T-Bills are available through any major brokerage (Fidelity, Vanguard, Schwab, TD Ameritrade) via secondary market purchases, though you may pay a small spread. The advantage of brokerages is consolidation with your other investment accounts and easier auto-reinvestment setup.
For a detailed walkthrough, see our guide: How to Buy Treasury Bills in 2026.
FAQ
Is this Treasury bill calculator free?
Yes, completely free with no signup required. All calculations run in your browser — your financial data is never sent to any server.
Is my financial data private?
Absolutely. Everything runs entirely in your browser using client-side JavaScript. No data is transmitted or stored anywhere.
What is the difference between discount yield and investment yield?
Discount yield (bank discount rate) expresses interest as a percentage of face value using a 360-day year — the way T-Bills are quoted at auction. Investment yield (bond equivalent yield) expresses interest as a percentage of your purchase price using a 365-day year, making it comparable to savings account APYs and CD rates.
What is a T-Bill ladder and why build one?
A T-Bill ladder spreads your investment across multiple maturities — for example, $50,000 split across 4-week, 8-week, 13-week, and 52-week T-Bills. As each rung matures, you reinvest at current rates. This provides regular liquidity, averages out interest rate changes, and avoids the risk of being locked into a single rate for a long period.
Are T-Bill gains subject to state income tax?
No. Interest earned on U.S. Treasury obligations, including T-Bills, is exempt from state and local income taxes. It is subject to federal income tax only. This makes T-Bills especially attractive in high-tax states like California, New York, and New Jersey, where the state tax exemption can be worth 0.2–0.5% in effective yield advantage.
How do T-Bills compare to high-yield savings accounts?
The key advantage of T-Bills over HYSAs and CDs is state tax exemption. In a state with 5% income tax, a T-Bill yielding 4.3% is equivalent to a savings account paying about 4.53%. In high-tax states like California (13%), a 4.3% T-Bill is equivalent to roughly 4.95% in a taxable account. The calculator's comparison section shows this break-even for your specific situation.
How do I buy Treasury bills?
You can purchase T-Bills directly from the U.S. Treasury at TreasuryDirect.gov with no transaction fees, or through a brokerage like Fidelity, Vanguard, or Schwab. Minimum purchase is $100. T-Bills are sold at a discount to face value and mature at full face value, so your return comes from the price difference.
What happens to my T-Bill at maturity?
At maturity, the Treasury deposits the full face value into your linked bank account or TreasuryDirect account. The difference between your purchase price and face value is your interest income, reported on Form 1099-INT for the tax year in which the T-Bill matures.
Are T-Bills safe investments?
T-Bills are considered the safest investment available. They are backed by the full faith and credit of the U.S. government and have never defaulted in American history. There is effectively zero credit risk. However, T-Bills do carry interest rate risk if you need to sell before maturity — rising rates cause secondary market prices to fall. Holding to maturity eliminates this risk entirely.
How do T-Bills compare to CDs?
Both T-Bills and CDs (certificates of deposit) are short-term, low-risk savings instruments. The key differences: T-Bills are exempt from state and local income taxes while CD interest is fully taxable. T-Bills are backed by the U.S. Treasury; CDs are insured by the FDIC up to $250,000 per bank. T-Bills are more liquid — they can be sold on the secondary market before maturity. CDs typically charge an early withdrawal penalty. In high-tax states, T-Bills often beat equivalent CD rates on an after-tax basis.