Treasury Bill Calculator
Work out a T-bill's price, the discount you earn, tax, and the annualised return. Works with yield or discount rates, any tenor and any currency.
Works for any country and currency. In Kenya? Use the Kenya calculator, set up for CBK's 91, 182 and 364-day bills.
| Face value | 10,000.00 |
|---|---|
| Price per 100 | 97.5675 |
| Price | 9,756.75 |
| Discount (income before tax) | 243.25 |
| Tax (0%, taken at maturity) | 0.00 |
| Same bill as a yield (365 days) | 5.00% |
| Same bill as a discount rate (365 days) | 4.88% |
How the calculator works
A Treasury bill pays no interest. You buy it for less than its face value and get the full face value back at maturity; the difference is the discount, your income. How the price is worked out depends on how the rate is quoted:
- Yield (a return on what you pay): price = face value ÷ (1 + rate × days ÷ days in a year).
- Discount rate (a discount off the face value): price = face value × (1 − rate × days ÷ days in a year).
The same 10% gives a lower price as a discount rate than as a yield, which is why it matters which one your auction notice uses. The results show both, so you can compare a bill with one quoted the other way.
Your return after tax is the income after tax divided by the cash you paid, turned into a yearly rate on a 365-day year. It's the figure to compare with a savings account or a money market fund.
An example
A 182-day bill with a face value of 10,000 at a 5% yield on a 365-day year costs 10,000 ÷ (1 + 0.05 × 182 ÷ 365) = 9,756.75. At maturity you receive 10,000: a discount of 243.25, or 5% a year on what you paid. With tax, enter your rate and choose when it's taken.
Estimates to help you plan, not financial or tax advice. Rates, conventions and tax rules change: check the figures against your own statement and your tax authority.
Frequently asked questions
How do you calculate the price of a Treasury bill?
It depends on how the rate is quoted. For a yield (a return on what you pay), price = face value ÷ (1 + rate × days ÷ year basis). For a discount rate (a discount off the face value), price = face value × (1 − rate × days ÷ year basis). The year basis is usually 360, 364 or 365 days.
Why doesn't my T-bill return match the quoted rate?
Quoted rates use a market convention, such as a 360- or 364-day year, or a discount on the face value rather than a return on what you paid. The annualised return here is on a 365-day year and on the cash you actually paid, after tax, so it is usually a little different.
Do Treasury bills pay interest?
No. You buy a bill below its face value and receive the full face value at maturity. The difference, the discount, is your income.
Is T-bill income taxed?
In many countries the discount is taxed like interest, and some withhold the tax at source. Enter your country's rate in the tax field; local rules vary, so check with your tax authority.