Treasury Bill Calculator

Treasury bills are quoted in a way that trips up newcomers, so this tool translates a discount rate into the figures that actually matter: what you pay up front, the interest you collect, and the equivalent annual percentage yield (APY). Having the APY in hand makes it straightforward to line T-bills up against other places you might put your money under the economic forecasts circulating for 2026.

The math follows standard T-bill conventions. Purchase price comes from Face Value * (1 - (Discount Rate * Days to Maturity / 360)), and interest earned is simply Face Value minus Purchase Price. To express the return as an annual yield, the calculator annualizes that interest against what you paid: ((Face Value - Purchase Price) / Purchase Price) * (365 / Days to Maturity).

A T-bill is bought below its face value and redeemed at the full amount, which is where the return comes from, so the discount rate is not the same thing as the yield you ultimately earn. The equivalent APY shown here settles that distinction. And while T-bills sit at the low-risk end of the spectrum, their returns still move with prevailing market conditions like any other investment.