AtlasCalcsUtility Calculation Suite
2026-09-22 7 min read

Treasury Bill Calculator

Treasury bill price and auction-equivalent yields for a treasury bond. Live calculator with worked steps, charts and formulas.

Calculator

T-Bill Face Value
$
Discount (Bank) Rate(%)
%
Days to Maturity(days)
days

This treasury & government calculator runs on standard bond mathematics: coupons and face value discounted at the market yield with 2 payment(s) per year. Money is calculated at full precision and rounded only for display.

Results

Optimal

Purchase Price

$9,773

Profit at Maturity

$228

Bank Discount Rate

4.50%

Investment (Bond-Equivalent) Yield

4.67%

Days to Maturity

182

Live results update as you type — currently showing purchase price of $9,773. Replace the defaults with your own quote for an exact comparison.

Visualizations

Discount vs Proceeds

Discount2%
Price paid98%

Formula

Treasury bill auction math: discount, price and bond-equivalent yield.

Price = Face × (1 − d·days/360)

Variables

SymbolNameUnitDescription
dDiscount ratepercentAuction discount

Explanation

Auction-equivalent price and yields for a T-Bill.

Step-by-Step Calculation

Follow each step to understand how the result is calculated from your inputs.

Step 1

Discount the face by the bank-discount formula.

Price = Face × (1 − d·days/360)
Discount:4.50%
Result: $9,772.50
Step 2

Profit is face minus price.

Profit = Face − Price
Result: $227.50
Step 3

Convert to bond-equivalent yield on a 365-day base.

Inv = (Profit/Price) × 365/days
Result: 4.67%
Final Answer
$9,773

Worked Examples

See how the calculator works with different scenarios.

Scenario

The treasury bill calculator run on the values above, showing the full calculation path rather than only the answer.

Inputs

T-Bill Face Value:10000
Discount (Bank) Rate:4.5
Days to Maturity:182

Calculation

1. Discount the face by the bank-discount formula. → $9,772.50 2. Profit is face minus price. → $227.50 3. Convert to bond-equivalent yield on a 365-day base. → 4.67%

Result

Purchase Price: $9,773

Interpretation

Pay $9,772.50 for $10,000 in 182 days; investment yield 4.67%.

Understanding Your Result

Your Result: Purchase Price: $9,773

What This Means

Auction-equivalent price and yields for a T-Bill.

Why It Matters

Pay $9,772.50 for $10,000 in 182 days; investment yield 4.67%.

Professional Interpretation

Pay $9,772.50 for $10,000 in 182 days; investment yield 4.67%.

How this is calculated

Treasury bill auction math: discount, price and bond-equivalent yield.

What drives the result

T-Bills are sold at a discount with no coupons; notes and bonds pay coupons. Municipal interest is typically federal-tax exempt, so compare on a taxable-equivalent basis. Savings bonds (I and EE) accrue or composite with inflation and reward holding to term.

Recommendations

  • •T-Bills are state/local-tax exempt — compare after-tax with CDs.
  • •Roll 4/8/13/17/26/52-week bills to build a cash ladder.

Educational Content

Introduction

Sovereign and government-linked bonds (Treasuries, T-Bills, municipals, savings bonds) share one trait: the credit backstop is a government. Pricing still follows present value, but tax treatment, auction mechanics and inflation linkage change the comparison.

Concept Explanation

T-Bills are sold at a discount with no coupons; notes and bonds pay coupons. Municipal interest is typically federal-tax exempt, so compare on a taxable-equivalent basis. Savings bonds (I and EE) accrue or composite with inflation and reward holding to term.

Applications

▸Parking cash in T-Bills versus a money-market fund after tax
▸Choosing municipal versus corporate bonds in a high tax bracket
▸Holding I Bonds as an inflation hedge or EE Bonds for a 20-year double
▸Rolling Treasury auctions into a cash ladder

Benefits

  • •Puts discount, coupon and tax-exempt structures on one comparable basis
  • •Converts muni yields to taxable-equivalent hurdles
  • •Shows T-Bill discount versus investment (bond-equivalent) yield
  • •Separates real yield from inflation compensation on linkers

Limitations

  • •State-tax and AMT treatment varies by issue and domicile
  • •Auction prices move between announcement and settlement
  • •CPI linkage lags actual inflation prints by months
  • •Early redemption penalties (savings bonds) change realized returns

Best Practices

  • •Compare T-Bills to CDs on an after-tax, same-day-count basis
  • •Rerun muni math at your exact marginal bracket
  • •Hold savings bonds to their guarantee dates (12 months minimum, 20 years for EE doubling)
  • •Track CPI reset dates for I Bonds and TIPS

Common Misconceptions

Myth: Treasuries are risk-free in every sense
Truth: Credit risk is minimal, but price risk from rate moves and inflation risk on nominal bonds remain.
Myth: A muni always beats a corporate
Truth: Only above a break-even bracket. Below it, the taxable bond wins after tax.

Practical Tips

  • •Auto-roll at TreasuryDirect to keep cash invested.

Common Mistakes

Forgetting the 360 vs 365 base
The two yields differ by construction.

Assumptions

This calculator makes the following assumptions to provide estimates:

U.S. Treasury backing: Minimal credit risk.

Limitations

Be aware of these limitations when using this calculator:

Limitation: State-tax and AMT treatment varies by issue and domicile
Limitation: Auction prices move between announcement and settlement
Limitation: CPI linkage lags actual inflation prints by months
Limitation: Early redemption penalties (savings bonds) change realized returns

Frequently Asked Questions

Answers to common questions about this calculator.

How are T-Bills sold?
At weekly auctions in 4/8/13/17/26/52-week tenors; state/local-tax exempt.
Who uses the treasury bill calculator?
It is used by investors comparing treasury bond options, by advisers checking a quote before a client commits, and by planners sizing contributions for a goal. It sits in the Treasury & Government group of the Bonds & Fixed Income section of Atlascalcs.
How accurate is the treasury bill calculator?
Every figure follows directly from the inputs using standard bond mathematics, so it is accurate to the quality of the values you enter. Dealer quotes round to cents and apply day-count conventions, so expect pennies of difference on accrued interest and settlement figures.
How current are the yields used here?
The calculator uses the figures you enter, so update the yield to your dealer quote or auction result. Market yields move intraday; ratio and tax thresholds follow the conventions in the references.
Does rounding change the results?
All math runs at full precision and rounds only for display. Dealers round to cents and apply day-count conventions, so expect pennies of difference on accrued interest.
Should I compare coupons or yields?
Always yields (YTM for total return, current yield for income). Two bonds with different coupons price identically at the same YTM.
What should I have ready before buying?
Face, coupon, maturity, frequency, price or yield, settlement date, tax bracket and any call or conversion terms. With those, every figure here ties to a quote.

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Glossary

Technical terms used in mortgage calculations explained in plain language.

T-Bill
U.S. Treasury bill (≤1 year) sold at a discount with no coupons.

Authoritative References

Trusted sources and standards referenced by this calculator.

Applicable Standards

Present-value pricing with periodic compounding at the quoted yieldYTM solved numerically (bisection) to full precision; display rounded onlyT-Bill bank discount on 360 days; investment yield on 365 daysMoney rounded for display only; all calculations run at full precision

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Page Information

Last Updated:

2026-09-22

Version:

2.0.0

License:

Free to use for educational and professional purposes.