Treasury Bill Calculator

What Is a Treasury Bill?

A US Treasury Bill (T-bill) is a short-term government debt security sold at a discount to face value and redeemed for the full face value at maturity. The difference between purchase price and face value is your interest. T-bills are auctioned in standard terms of 4, 8, 13, 17, 26, and 52 weeks at TreasuryDirect.gov with a minimum purchase of $100. They are backed by the full faith and credit of the US government and interest is exempt from state and local income tax.

Unlike bonds or CDs, T-bills do not pay periodic coupons. You pay less than face value up front, and your return is realized as a single payment at maturity. This makes T-bills attractive for parking cash that you will need at a specific future date.

How Discount Rate Becomes Real Yield

The Treasury quotes T-bills using a bank discount rate on a 360-day basis, not a true yield. Purchase price equals face value times one minus discount rate times days divided by 360. The investment yield (bond equivalent yield, or BEY) is calculated on the actual 365-day year and the price paid, not face value, so it is always higher than the discount rate. This calculator reports both so you can compare T-bills apples-to-apples with CDs and high-yield savings accounts, which quote APY on a 365-day basis.

For example, a 4.30 percent discount rate on a 13-week T-bill equals roughly a 4.41 percent investment yield. At a 22 percent federal bracket with 5 percent state tax, the after-tax yield on a T-bill beats a similarly rated CD by the state tax savings alone.

T-Bill vs High-Yield Savings vs CD

High-yield savings accounts are fully liquid and FDIC-insured but rates move with the Fed, and interest is taxed at both federal and state levels — see our HYSA interest calculator for a side-by-side comparison. CDs lock in a rate but charge early-withdrawal penalties and are also fully taxable; the CD vs savings comparison tool shows breakeven yield. T-bills hold the state-tax exemption advantage and are easy to ladder: buy a new 13-week T-bill every month and you will have one maturing every 4 weeks for steady cash flow. During periods of inverted yield curves, short T-bills can yield more than 2-year Treasuries.

Common use cases: emergency fund above the FDIC limit, cash earmarked for a home down payment in the next 12 months — pair this with a down payment savings calculator — or a short-term parking spot for a tax refund or year-end bonus.

Current 2026 T-Bill Rates and Auction Schedule

As of April 2026, US Treasury auction discount rates have ranged 4.10 to 4.45 percent on the 13-week bill and 4.20 to 4.55 percent on the 26-week bill, broadly tracking the federal funds rate target band of 4.25 to 4.50 percent set after the March 2026 FOMC. The 4-week and 8-week bills are auctioned every Tuesday with settlement Thursday; 13-week and 26-week bills auction Mondays with Thursday settlement; the 52-week bill auctions every fourth Tuesday. Bid noncompetitive at TreasuryDirect.gov to lock the auction-clearing rate without specifying a yield. For a real-time inflation comparison, run the same face value through our I Bond calculator and the bond yield calculator.

T-Bill Ladder Strategies for Different Goals

A 4-week T-bill ladder generates steady weekly liquidity — buy one new 4-week bill every Tuesday, and after one cycle you have a bill maturing each Thursday. This setup beats a savings account by roughly 30 to 50 basis points after state taxes for residents of California, New York, Oregon, and Massachusetts. A 13-week ladder using $50,000 across four 13-week bills purchased one month apart yields the higher 3-month rate but still releases $12,500 every 4 weeks for any need. For longer horizons, mix 26-week and 52-week bills to capture the steeper part of the curve when long rates exceed short — confirmed by checking the compound interest calculator at expected reinvestment yields. Reinvest matured proceeds via the TreasuryDirect schedule-reinvestment feature to avoid cash drag.

T-Bill Auto-Roll: How to Automate Reinvestment at TreasuryDirect

TreasuryDirect.gov offers a schedule-reinvestment feature that automatically rolls maturing T-bills into the next auction of the same term — up to 25 consecutive reinvestments. Set it once and your 13-week ladder renews itself for over six years without logging in. To adjust the reinvestment, log in before the auction date and change the number of remaining reinvestments or cancel. There is no fee and the reinvestment uses the new auction clearing rate, so your yield adjusts with the market. Pair auto-roll with a savings rate calculator to set an annual target and let auto-roll handle the execution. For investors who prefer brokerage convenience, Fidelity and Schwab offer similar auto-roll features through their Treasury auction programs with no commission.

Comparing T-Bill Returns Across Investment Amounts

T-bills scale linearly — double the face value, double the interest — but after-tax returns shift based on total portfolio income. At a $10,000 face value with a 4.30% discount rate on a 13-week bill, you earn roughly $108.69 before tax. At $100,000, that becomes $1,086.94. The state-tax exemption advantage grows with larger amounts: a California resident (13.3% top state rate) holding $100,000 in T-bills saves approximately $144 per 13-week cycle versus a taxable HYSA at the same pre-tax rate. Over a full year of rolling 13-week bills, that compounds to roughly $576 in state tax savings alone. Use our compound interest calculator to project multi-year growth and our lean FIRE calculator to see how T-bill income fits into early retirement planning. Source: TreasuryDirect.gov auction results, April 2026.

OBBB 2026 Tax Update — What It Means for T-Bill Investors

The One Big Beautiful Bill Act (P.L. 119-21, signed July 4, 2025) extended or made permanent many TCJA provisions that were originally set to sunset December 31, 2026. The previously feared revert to 2017 brackets (top 39.6%, 22% bracket becoming 25%) was largely averted by OBBB. T-bill interest remains fully federally taxable but the federal-bracket landscape is now more stable than the old "sunset cliff" narrative suggested. The state-tax exemption stays in place, preserving the after-tax advantage over CDs and HYSAs for high-tax-state residents (California, New York, Oregon, Massachusetts). For estate planning, the basic exclusion amount was raised to $15 million for 2026 — NOT halved as originally feared. Use our US income tax calculator to model your post-OBBB bracket. Source: irs.gov OBBB pages and the US Treasury. Last updated April 2026.

Can You Sell a T-Bill Before Maturity?

Yes. Unlike a CD, a T-bill has no early-withdrawal penalty — but it is not redeemed early by the Treasury either. To get cash before maturity you sell the bill on the secondary market at its current market price. On TreasuryDirect you must first transfer the bill to a brokerage account (Fidelity, Schwab, Vanguard) to sell; in a brokerage you can sell directly. Because the price moves inversely to interest rates, an early sale can return slightly more or less than you paid:

The accrued discount is still taxed as interest; any extra gain or loss versus that accrued amount is a short-term capital gain or loss reported on Schedule D. Because most T-bills mature within a year, holding to maturity usually avoids this complexity entirely. Source: IRS Publication 550 and TreasuryDirect.gov.