Tools · Fixed income
Treasury Bill Calculator
See what a treasury bill really pays — the discounted price, the interest and the after-tax yield — for any East African market. Free, and nothing is stored.
Bills are sold at a discount: you pay less than the face value and are repaid the full face value at maturity. Enter the auction yield and set the withholding tax to your market's rate.
- You pay (price)
- KES 909,317
- Face value at maturity
- KES 1,000,000
- Interest (gross)
- KES 90,683
- Interest (after tax)
- KES 77,080
- Effective yield, after tax
- 8.50%
01How the numbers work
A treasury bill has no coupon. Instead it is sold at a discount: you pay less than the face value and collect the full face value at maturity, and that gap is your interest. The shorter the tenor or the higher the yield, the smaller the price you pay today.
The effective yield restates that return as an annual percentage, so a 91-day and a 364-day bill can be compared on equal terms. Withholding tax is taken off the interest at source, so the after-tax figure is what actually reaches you.
Buying bills in a specific market?
Rates, minimums, tax and the rules for foreign investors, market by market:
02Common questions
How is a treasury bill's return calculated?
A bill is sold at a discount: you pay less than its face value and are repaid the full face value at maturity. The calculator works out the price from the auction yield and the tenor, then shows the interest (face minus price) and the effective annual yield, gross and after tax.
What is the difference between the discount and the yield?
The discount is the cash interest — the gap between price and face value over the life of the bill. The yield restates that as an annual percentage, so you can compare a 91-day and a 364-day bill on equal terms. This calculator takes the annual yield as the input.
Does this account for tax?
Yes. Enter your market's withholding tax and the calculator shows the after-tax interest and yield. Treasury-bill interest is taxed at 15% in Kenya, 20% in Uganda, 15% in Tanzania and 15% in Rwanda — see the country guides.
Which day-count does it use?
A 365-day year, the convention for East African treasury bills. Bills are quoted to 91, 182 and 364 days, and the calculator has quick buttons for each.
Rolling bills over? Skip the spreadsheet.
Tamias keeps the yield, value and after-tax return of every bill, bond and share you own up to date, and nudges you before each maturity — across Kenya, Uganda, Tanzania and Rwanda.
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