TBILLEQ Function in Google Sheets: Formula, Examples & Troubleshooting

=TBILLEQ(settlement, maturity, discount)

settlement is the date the buyer receives the security. maturity is its redemption date. discount is the purchase discount rate, supplied as a percentage such as 4% or a decimal such as 0.04. Google documents no optional basis, frequency, price, or face-value argument. Use DATE or existing date-valued cells for the first two arguments. Google TBILLEQ reference.

The third input is a discount rate. If your starting information is a price of 99, it cannot be passed as discount without first establishing the corresponding discount quote.

1. Enter =TBILLEQ(B2,B3,B4) in B6.
2. Apply percentage formatting with six decimal places. Expected result: 4.096521%.
3. Enter =B3-B2 in B7 and display it as a number. Expected interval: 90 days.
4. In B8 calculate the illustrative price: =100*(1-B4*B7/360). Expected price: 99 per 100 face value.
5. In B9 enter =((100-B8)/B8)*365/B7. Expected result: 4.096521%.

An algebraically equivalent audit for these inputs is:

=365*B4/(360-B4*(B3-B2))

The discount uses a face-value reference, whereas the return uses the amount paid. The annualization in this short-term audit uses 365 days for the equivalent return. Do not erase those differences by simply renaming the original 4% discount cell “yield.”

Google publishes a bill settling February 1, 2011, maturing June 30, 2011, with discount 2.5%. The displayed TBILLEQ output is 0.02561223774. The interval is 149 actual days. The expression 365*0.025/(360-0.025*149) independently reproduces the published output. Google’s published TBILLEQ example.

That published example supports the ordinary short-term calculation above. It does not establish every boundary rule or a long-maturity algorithm. The general expression is used here to audit the stated short-term cases; a complete formal algorithm across all possible inputs is not supplied by the reviewed Google prose.

Keep settlement in B2 and discount in B4. Enter 91 and 182 in D2:D3. In E2 enter =$B$2+D2 and fill down; these are dates 91 and 182 days after settlement. In F2 enter =TBILLEQ($B$2,E2,$B$4) and fill down.

The equivalent rate changes even though the quoted discount remains 4%. The longer interval reduces the modeled purchase price, changing the amount-invested denominator. This is a controlled mathematical comparison, not evidence that one actual security is preferable.

For the original 90-day inputs, three distinct outputs are useful: discount 4%, 360-day price-based annualization 4.040404%, and the equivalent annual return 4.096521%. Write the convention in each column heading. A bare heading such as “rate” hides the reason for the differences.

Google’s published error sheet displays #NUM! for March 31, 2008 to June 1, 2009 at 9%, and for reversed dates from March 31, 2009 to June 1, 2008 at 9%. These are concrete published failures, not fresh tests. Another row combines a negative discount with an overlong term; it does not independently isolate the negative-discount rule. Published error examples.

Check chronology, actual day count, and percentage scaling before suppressing an error. The reviewed TBILLEQ prose does not specify a complete valid-domain/error map. This guide does not claim exact zero-rate behavior, exact one-year/leap-year limits, fractional-date handling, or an unverified long-term branch. The worked scenarios deliberately remain at or below 182 actual days.

TBILLEQ is currently documented by Google. An introduction date, earliest functioning version, and retirement date were not established. Similar names in other spreadsheet applications do not verify identical limits or formulas. TBILLEQ takes a discount rate; TBILLYIELD takes a price. That input distinction matters when importing a worksheet.

Related: DATE, ISNUMBER, and ROUND.

References checked October 17, 2026: Google TBILLEQ contract and published numerical example.