What T-bills really pay, next to your bank's fixed deposit.
Amount to invest
₦
T-bill stop rate
%
Bank FD rate
%
Defaults from the 2026-06-10 auction. Edit to match the rate your bank or app quotes.
T-bill payout · 364 days
₦1,202,260
You invest today₦1,000,000
Face value bought (at ₦81.65 per ₦100)₦1,224,734
Discount earned+ ₦224,734
WHT (10%)− ₦22,473
True yield (gross / after tax)22.54% / 20.28%
+₦94,556
more than a fixed deposit at 12% over the same 364 days, after tax on both.
Side by side, after 10% WHT
T-bill
Fixed deposit
quoted rate
18.40%
12.00%
after-tax yield
20.28%
10.80%
interest kept
₦202,260
₦107,704
you get back
₦1,202,260
₦1,107,704
How this calculator works
Treasury bills are quoted in a way that undersells them. The stop rate from the CBN auction is a discount rate: it is calculated on the face value of the bill, not on the cash you actually hand over. Because you buy at a discount, your real return on money invested is always higher than the quoted rate, and the gap widens with longer tenors. This calculator starts from the cash you want to invest, works out how much face value that buys at your stop rate, and shows the discount you earn as both naira and a true annualised yield.
It then applies the tax. Since 28 October 2025, interest on treasury bills, fixed deposits and other short-term instruments attracts 10% withholding tax at source under the Nigeria Tax Act 2025 regime. The decade-old pitch that T-bills are tax-free is no longer true; only FGN bonds and CBN OMO bills keep their exemption. Both sides of this comparison are shown after the same 10% deduction, which is the only fair way to line them up.
The fixed deposit side uses simple interest at the rate you enter, held to maturity. Retail FD rates vary widely by bank and by how hard you negotiate, so the default is only a starting point: put in the rate your bank actually offered you. The comparison chip shows the after-tax naira difference on your amount over the same tenor. Rates here are manual, like everything on SabiCalc: defaults are from the auction date shown in the masthead, and every figure recalculates when you edit them. Estimates only, not investment advice.
Frequently asked questions
How do treasury bills work in Nigeria?
Treasury bills are short-term Federal Government debt sold at a discount through CBN auctions in 91, 182 and 364 day tenors. You pay less than face value today and receive the full face value at maturity; the discount is your interest. You can buy at the primary auction through your bank (commonly from about N50,000) or through licensed investment apps, which also offer secondary market access.
What is the difference between the stop rate and the true yield?
The stop rate is a discount rate, calculated on the face value. But you only pay the discounted price, so your actual return on the cash you put down is higher. For example, an 18.4% stop rate on a 364 day bill means you pay about N81.65 per N100 of face value, which works out to a true yield of roughly 22.5% on your money before tax. This calculator always shows both numbers.
Are treasury bills still tax-free in Nigeria?
No. From 28 October 2025, under the Nigeria Tax Act 2025 regime, interest on treasury bills and other short-term instruments attracts 10% withholding tax, deducted at source, for both individuals and companies. FGN bonds and CBN OMO bills remain exempt. This calculator deducts the 10% WHT from both the T-bill and the fixed deposit so the comparison is honest.
Are treasury bills better than a fixed deposit?
On rate, usually yes: T-bill stop rates have run well above typical retail fixed deposit rates, and both are now taxed the same 10% on interest. Fixed deposits win on flexibility in some cases: any amount, any start date, and you can break them early (usually forfeiting some interest), while selling a T-bill before maturity depends on secondary market prices. Both are very low risk: T-bills are FGN obligations, deposits are NDIC-insured up to the coverage limit.
What is the minimum amount and how do I buy?
Through most banks, the practical minimum for the primary auction is about N50,000, with bids in multiples above that; some investment apps let you start smaller via the secondary market. You submit a bid through your bank or app before the auction (usually every two weeks), and the CBN's stop rate determines whether your bid is filled.
Method: T-bill price = face value discounted at the stop rate for the tenor (365-day year). True yield = discount earned over cash invested, annualised. 10% WHT deducted from interest on both instruments (FIRS, effective 28 Oct 2025). Fixed deposit uses simple interest to maturity. Auction results, secondary market prices and bank FD quotes vary. Not investment advice.