Nigeria Treasury Bills Calculator

Estimate the purchase price, discount income, true yield, and after withholding tax proceeds for a Nigerian Treasury Bill quoted on a discount rate basis.

Your entries stay in your browser. This calculator does not store, transmit, or sell the figures you enter.

What amount do you know?

Enter the cash amount used to buy the bill, before any separate dealer or platform fees.

Standard Nigerian Treasury Bill tenors are 91, 182, and 364 days.

Enter the discount or stop rate quoted for the bill, not the true yield. Rates change by auction. Check CBN government securities data.

Advanced option

The calculator uses 365 by default. Use 366 where the applicable pricing convention for the bill uses a leap year basis.

Enter the discount rate and calculate to see the estimated return.

How this Nigeria Treasury Bills calculator works

Nigerian Treasury Bills are short term government securities issued at a discount. Instead of paying periodic interest, the investor buys the bill for less than its face value. The difference between the purchase price and the face value is the gross discount income.

The Central Bank of Nigeria describes NTBs as discount securities and commonly uses 91-day, 182-day, and 364-day tenors. CBN government-securities data also separates the auction rate from the “true yield,” which is why this calculator shows both the quoted discount rate and the return on the cash actually invested.

Formula used

Discount income = Face value × Discount rate × Days ÷ Day count basis

Purchase price = Face value − Discount income

Face value from a known cash investment = Purchase price ÷ (1 − Discount rate × Days ÷ Day count basis)

Gross true yield = (Discount income ÷ Purchase price) × (Day count basis ÷ Days)

In plain English, the quoted discount rate is applied to the face value, not to the cash paid for the bill. Because the purchase price is lower than the face value, the annualised true yield on the cash invested is normally higher than the quoted discount rate.

How withholding tax is treated

This calculator applies 10% withholding tax to the Treasury Bill's discount income by default. The tax amount is deducted from the estimated maturity proceeds. You can turn the deduction off when it does not apply to the calculation you are making.

Important: Tax treatment can depend on the investor, transaction, and applicable law. This tool is an estimate, not a tax assessment. For a filing or compliance decision, use the treatment confirmed by the relevant tax authority or a qualified tax professional.

What the result includes

  • The estimated amount paid for the bill.
  • The face value before withholding tax.
  • Gross discount income.
  • Estimated withholding tax where selected.
  • Net income and estimated maturity proceeds.
  • Gross true yield and after tax annualised yield.
  • The net return over the actual holding period.

Important limitations

The calculator is designed for an NTB quoted on a discount rate basis. A bank, broker, or investment platform may quote a secondary market yield or an all in price instead. In that case, its result may differ from this simple discount-pricing method.

The estimate does not include dealer spreads, brokerage, custody charges, platform fees, settlement costs, or a change in market value if the bill is sold before maturity. It also does not forecast future auction rates.

Methodology and sources

The calculation uses the bill's face value, annual discount rate, days to maturity, and selected day count basis. The default basis is 365 days, with a 366-day option for a leap year basis. Results are rounded for display, while the JavaScript keeps the underlying calculation at full precision.

Methodology last reviewed: 23 September 2026.