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Treasury Bill Discount Rate Calculator

Work out treasury bill discount rate instantly with clear inputs, formula shown and shareable results.

About Treasury Bill Discount Rate Calculator

Bills are quoted on a discount basis using a 360-day year and dividing by face value, which understates the true return. Converting to an investment yield on price with a 365-day year gives the figure comparable with deposits.

Formula

Discount to yield

Discount = F × rate × days/360; investment yield = discount/price × 365/days

Worked example

With the default values below, Treasury Bill Discount Rate Calculator returns Purchase Price of $9,826,847.22. Change any input above and every figure here is recalculated in your browser.

Inputs used

Face Valueminimum 0
10,000,000
Quoted Discount Rateaccepts 0–100 %
6.85 %
Days To Maturityaccepts 1–366
91

Results

Purchase Price
$9,826,847.22
Discount Amount
$173,152.78
Equivalent Investment Yield
7.0675%
Gap Between The Two Conventions In Basis Points
21.8

Step by step

  1. 1Values used
  2. 2Discount to yield
  3. 3Purchase Price= 9,826,847.22
  4. 4Discount Amount= 173,152.78
  5. 5Equivalent Investment Yield= 7.0675
  6. 6Gap Between The Two Conventions In Basis Points= 21.8

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Figures are estimates based on the inputs given. Bank charges, regulatory minima and market rates change and differ between institutions and jurisdictions. This is not financial advice — confirm with your bank or treasury policy.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Figures are estimates based on the inputs given. Bank charges, regulatory minima and market rates change and differ between institutions and jurisdictions. This is not financial advice — confirm with your bank or treasury policy.

Frequently Asked Questions

Why do two conventions coexist?

The discount basis is a legacy auction convention; the investment yield is what investors actually earn.

Which is always larger?

The investment yield, because it divides by the smaller price and uses a 365-day year.

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