Disclosure & Disclaimer
Not Financial Advice
The T-Bill Calculator website and all tools, content, and results provided on this site are for informational and educational purposes only. Nothing on this website constitutes financial, investment, tax, or legal advice. You should not rely on any calculation or information provided here when making investment decisions.
Always consult a qualified financial advisor, tax professional, or attorney before making any investment or financial decision.
Accuracy of Calculations
Our calculators use standard U.S. Treasury formulas based on the bank-discount basis with a 360-day year for discount calculations and a 365-day year (366-day in leap years) for annualized yield — consistent with U.S. Treasury conventions. For annualized yield, a 366-day year is used when the holding period spans February 29 in a leap year, following standard Treasury convention. However, actual T-Bill prices, yields, and returns may differ due to:
- Auction-specific pricing and competitive bidding
- Accrued interest adjustments
- Brokerage fees or transaction costs
- Changes in tax law or individual tax circumstances
- Rounding differences applied by TreasuryDirect or brokers
We make no guarantee that calculator results will exactly match amounts shown on TreasuryDirect.gov or your brokerage account.
Tax Information
T-Bill earnings are generally subject to federal income tax and are exempt from state and local taxes under federal law. However, tax treatment can vary based on individual circumstances. The after-tax calculations on this site are estimates only and do not account for the Alternative Minimum Tax (AMT), net investment income tax, or other individual tax situations.
Please consult a qualified tax professional for advice specific to your situation.
Where this site calculates a combined federal and state tax rate (for example, in CD tax-equivalent yield comparisons), it uses a multiplicative formula: Combined Rate = 1 − (1 − Federal Rate) × (1 − State Rate). This is more accurate than simply adding the two rates, which overstates the combined tax burden.
No Affiliation with U.S. Treasury
This website is an independent, privately operated tool and is not affiliated with, endorsed by, or sponsored by the U.S. Department of the Treasury, TreasuryDirect.gov, the Federal Reserve, or any government agency.
External Links
This site may contain links to third-party websites such as TreasuryDirect.gov. These links are provided for convenience only. We have no control over the content of external sites and accept no responsibility for them or for any loss or damage that may arise from your use of them.
Investment Risk
While U.S. Treasury Bills are backed by the full faith and credit of the U.S. government and are considered among the safest investments available, all investments carry risk. Past yields are not indicative of future results. Interest rates fluctuate and future T-Bill auction rates cannot be predicted.
Changes to This Disclosure
We reserve the right to update or modify this disclosure at any time without prior notice. Continued use of this website after any changes constitutes your acceptance of the updated terms.