TBillLab

T-Bill Yield Calculator

Convert a T-bill discount into its real annualized yield (BEY).

Your T-bill numbers never leave your browser — all math runs locally.
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Try: Face value=1000, Purchase price=980, Days to maturity=182 → $1,000, $980, $20, 0.0396%, 0.0409%, 0.0409%

How to use

Enter the face value, what you pay, and the days until maturity. The calculator shows the Bank Discount Yield and the Bond Equivalent Yield (BEY) — the number to compare with CDs.

FAQ

Why two yields?

BDY divides the discount by face value; BEY divides by your actual price and uses a 365-day year, so BEY is the honest comparison.

Are T-bill results taxed?

Interest is federal-tax-free but state-taxable; that tax edge is not in the yield math.

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