Treasury Bill Yield Calculator
Use your purchase price and remaining term to compare discount yield, investment yield and an effective annual equivalent. No live or preset market rates are supplied.
Your maturity estimate
Why the yields differ
Let F be face value, P purchase price, d remaining days and Y the selected 365- or 366-day year. Earnings = F − P. Holding-period return = (F − P) / P.
Discount yield = (F − P) / F × 360 / d. It uses face value rather than invested dollars.
Investment yield uses purchase price. Up to half a year, it is (F − P) / P × Y / d. Longer bills use the coupon-equivalent formula: solve P × [1 + (d / Y − 0.5) × i] × (1 + i / 2) = F for i.
Simple annualized return always scales the holding return by Y / d. For longer bills this differs from the investment yield above.
Effective annual equivalent = (F / P)^(Y / d) − 1. It compounds the holding return for comparison; it is not a quoted auction investment rate or a prediction.
Input and result assumptions
The calculator accepts 1 to 366 remaining calendar days and requires a positive price and face value. A price above face value is allowed and produces negative earnings and yields. The maturity date is settlement plus entered days; confirm the actual security's maturity date, since no weekend or holiday adjustment is made. The selected year basis is used for both annual equivalents, while discount yield always uses 360 days.
No coupon payments, fees, taxes or early-sale price changes are modeled. Dollar results display cents, but calculations retain the entered price precision. If extreme inputs make the effective annual equivalent too large to represent, it is marked outside the numerical range while other results remain available. No market-rate feed is embedded: enter an auction or broker price that you have verified.
Sources: TreasuryDirect: Pricing and interest rates and Treasury bill pricing and investment-rate formulas.