Discount Yield
3.96%
US Treasury Bill Calculator
Calculate the discount yield and investment (bond-equivalent) yield of a T-Bill.
Bond-Equivalent Yield
4.09%
Discount Amount
$200.00
Days to Maturity
182
How to use the US Treasury Bill Calculator
The US Treasury Bill Calculator is free and runs entirely in your browser — no sign-up, and nothing you enter leaves your device. It opens pre-filled with a realistic example, so you can see how it works before replacing any figure with your own; the results update as you type. Press Calculate to refresh the result panel, or Reset to return to the example.
The inputs it asks for:
- Face Value — a dollar amount.
- Purchase Price — a dollar amount.
- Days to Maturity — a number.
The formula
A Treasury bill pays no coupon — you buy it below face value and receive face at maturity. The calculator expresses that gain two standard ways: the discount yield (against face value, on a 360-day basis) and the investment/bond-equivalent yield (against your actual price, on a 365-day basis):
Discount yield = (Face − Price)/Face × 360/days
Bond-equivalent yield = (Face − Price)/Price × 365/days- Face − Price
- the discount, which is your entire return
- days
- days to maturity
The two conventions exist for good reasons but aren't directly comparable to a normal bond yield. The bond-equivalent (investment) yield — measured against the price you actually pay and a 365-day year — is the fairer number for comparing a T-bill to other investments.
Worked example
Using the example values — Face Value $10,000.00, Purchase Price $9,800.00, Days to Maturity 182 — the US Treasury Bill Calculator returns a Bond-Equivalent Yield of 4.09%. It also reports Discount Yield (3.96%), Discount Amount ($200.00), Days to Maturity (182).
Prefer your own numbers? Change any field above and this recomputes instantly.
Key terms
- Treasury bill (T-bill)
- A short-term (≤1 year) US government debt security sold at a discount.
- Discount yield
- Return stated against face value on a 360-day year — the quoting convention.
- Bond-equivalent yield
- Return against the purchase price on a 365-day year — better for comparison.
- Discount
- Face value minus purchase price; the T-bill's entire return.
Frequently asked questions
Why are there two yields?
Convention. The discount yield (360-day, vs face) is how bills are quoted; the bond-equivalent yield (365-day, vs price) restates it so you can compare to coupon bonds and other investments.
Which yield should I compare?
The bond-equivalent (investment) yield. It's measured against what you actually paid, so it reflects your real return more honestly than the discount yield.
Is T-bill interest taxable?
It's subject to federal income tax but exempt from state and local tax — a modest advantage for investors in high-tax states.