Updated 18 October 2026
Use this 91-day T-bill calculator to work out what a Kenyan Treasury bill earns after tax. At the Central Bank of Kenya auction of 15 October 2026 (value date 19 October), the 91-day T-bill cleared at a weighted average rate of 8.75%.
Rates are what was last published, gross of tax. Money market funds are compounded monthly; bills, bonds, deposits and SACCO returns are worked out as simple interest. Your actual return will differ.
Set the period to 3 months to match the bill. The calculator treats the rate as simple interest over the term, which is close to how a bill pays. See how it stacks up against money market funds and bonds on the investment returns calculator.
91-day T-bill rate this week
The 91-day T-bill averaged 8.75% at the 15 October 2026 auction. Rates are set every week at the CBK auction, held on Thursdays, so check the latest result before you bid. Other bills: see the 182-day and 364-day pages.
How much KES 100,000 earns in a 91-day T-bill
On KES 100,000, the 91-day T-bill pays about KES 2,188 before tax and KES 1,859 after the 15% withholding tax over the 3-month term.
How a Treasury bill pays
A T-bill is sold at a discount. You pay less than the face value and receive the full face value when it matures, so the difference is your interest. For example, at the 15 October auction the price of the bill at the average rate was below KES 100 for every KES 100 of face value, and you get the full KES 100 back at maturity.
Minimum investment and how to buy
The minimum is KES 50,000 in face value. You buy through the CBK DhowCSD platform, on the web or the mobile app, after opening a CDS account with your ID and KRA PIN. You can place a competitive bid at a rate you choose or a non-competitive bid that takes the average rate. Payment is due by the value date, usually the Monday after the auction.
Tax and getting your money back
The interest is subject to a 15% withholding tax. At maturity the money goes to the bank account linked to your CDS account. You can also roll it over into a new bill. Selling before maturity is possible through the secondary market but is not straightforward for small investors.
Frequently asked questions
What is the 91-day T-bill rate in Kenya?
8.75% at the CBK auction of 15 October 2026.
What is the minimum amount for a T-bill in Kenya?
KES 50,000 in face value, bought through DhowCSD.
Is T-bill interest taxed?
Yes, at 15% withholding tax.
When are T-bill auctions held?
Every week, with bids closing on Thursday and settlement the following Monday.
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