Treasury Bill (T-Bill) Calculator
Calculate purchase price, discount rate, investment yield (BEY), and profit on US Treasury Bills (4, 8, 13, 26, and 52-week T-Bills).
What this calculator does
The Treasury Bill (T-Bill) Calculator estimates your result instantly from the values you enter, using standard investing & wealth formulas. Calculate purchase price, discount rate, investment yield (BEY), and profit on US Treasury Bills (4, 8, 13, 26, and 52-week T-Bills). Calculations run in your browser, so nothing you type is sent to a server, and the output is an estimate for planning rather than financial advice.
Treasury Bill (T-Bill) Calculator Results
T-Bill Purchase Price
- Interest Earned —
- Investment Yield (BEY) —
What This Means
About Treasury Bill (T-Bill) Calculator
The Treasury Bill (T-Bill) Calculator computes purchase price, total dollar interest, Bank Discount Rate, and Investment Yield (Bond Equivalent Yield / APY) for short-term US Treasury Bills sold at a discount to face value.
Formula & Mathematical Calculation
T-Bill Purchase Price = Face Value × [ 1 - ( Discount Rate % × Days to Maturity / 360 ) ]
Investment Yield (BEY %) = [ ( Face Value - Purchase Price ) / Purchase Price ] × ( 365 / Days to Maturity ) × 100
Calculation Example
$10,000 26-Week (182-Day) T-Bill @ 5.20% Discount Rate: Purchase Price = $9,737.11 → Interest Earned = $262.89 | Investment Yield (BEY) = 5.41% APY (State & Local Tax Exempt!).
Key Benefits
- Calculates exact purchase price and interest on US Treasury Bills
- Converts Bank Discount Rate into true Bond Equivalent Yield (BEY)
- Supports 4-week, 8-week, 13-week, 26-week, and 52-week T-Bills
- Accounts for state and local income tax exemption benefits
- 100% free government bond tool
How to Use this Calculator
-
Enter Total Face Value
Input total par amount (e.g. $10,000). -
Select T-Bill Maturity Term
Choose 4, 8, 13, 17, 26, or 52 weeks. -
Enter Auction Discount Rate (%)
Input quoted discount rate. -
Calculate Yield
Click Calculate to view discount price, dollar return, and true APY.
Assumptions & Limitations
What the calculation assumes
- Every value you enter is treated as an exact, known amount.
- Rates and contributions are assumed to stay constant for the whole period unless the form asks for them separately.
- Results use standard financial formulas and ignore fees, penalties and promotional terms that are not entered above.
- Inflation, tax changes and market volatility are not modelled unless a field for them is provided.
- Amounts are unit-agnostic: results are returned in the same currency you enter.
What it does not cover
- Treasury Bill (T-Bill) Calculator produces estimates for education and planning, not a quote, offer or professional advice.
- Real-world outcomes differ when fees, taxes, rounding rules or provider-specific terms apply.
- Local regulations and tax rules vary by country and change over time; verify current rules for your jurisdiction.
- Figures are only as accurate as the inputs you supply — check them before acting on the result.
- For decisions with lasting financial impact, confirm the numbers with a qualified professional.
Frequently Asked Questions
Free to use, no account needed. Calculations run in your browser, so nothing you type is sent to a server. Results are estimates — how we build and check our calculators.
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