TBILLYIELD Function in ONLYOFFICE Spreadsheet Editor: Syntax and Examples

For price 97.5, settlement January 15, 2026 and maturity April 15, 2026, the inspected ONLYOFFICE 10.0.0.169 source predicts approximately 0.101437024514, or 10.1437024514%, from =TBILLYIELD(DATE(2026,1,15),DATE(2026,4,15),97.5).

This source-derived result uses an internal day count of 91, although the actual calendar interval is 90 days. The function therefore should not be assumed to match a generic actual-day bill-yield formula or another spreadsheet implementation. These examples have not been executed in the application.

=TBILLYIELD(settlement, maturity, pr)

The official help defines pr as purchase price per 100 face value and describes maturity within one year. Use a positive price such as 97.5, not 97.5% (which would store 0.975). The output is an annual decimal yield; use percentage formatting for display. There is no day-count selector or redemption argument.

The wrapper constructs an internal n from a 360-day helper and then adds one for modern maturity serials. It computes ((100−pr)/pr) × 360/n and rejects n above 360.

The caller passes zero-based UTC month numbers to a helper that otherwise treats months as one-based. Therefore this path must not be described simply as standard US30/360. February and month-end adjustments can be affected. The examples below deliberately use uncomplicated 15th-of-month dates and report the traced n explicitly.

1. Enter =DATE(2026,1,15) in A2 and =DATE(2026,4,15) in B2.
2. Enter price 97.5 in C2.
3. Put =TBILLYIELD(A2,B2,C2) in D2.
4. Keep a separate note that the source path uses n=91 for this case; do not label it “90 actual days.”

The helper’s unadjusted difference is 3×30=90; the wrapper adds 1. The price gain ratio is (100−97.5)/97.5=1/39. Annualizing by 360/91 gives 0.101437024514 approximately.

The exact one-calendar-year example is rejected by this n>360 check, whereas TBILLPRICE’s separate calendar-year check permits the analogous dates. The help’s broad maturity description does not establish identical boundaries across the three bill functions.

An independent actual 90-day investment yield for the same 97.5-to 100 cash flow would be ((100−97.5)/97.5)×360/90≈0.102564102564. That is a mathematical comparison, not a claim about TBILLYIELD’s output in this version. The discrepancy comes from the day-count path, not from price rounding.

If a workflow requires a specified actual-day market convention, verify its formula and the target application separately. Do not silently label the source-derived 91-day result as an actual 90-day yield. Nor should a zero yield at price 100 be treated as evidence that the date logic is correct; the zero numerator hides any day-count difference.

The source rejects nonpositive price, settlement at/after maturity, unsupported date serials and internal n>360. Boolean scalar inputs have a #VALUE! branch and empty scalars a #N/A branch. Dates are floored. A price above 100 can produce a negative yield because the wrapper does not require a discount to par.

The worked predictions do not validate every month-end, February or historical-date case. This guide documents the inspected implementation and its limitations; it does not certify the result for an actual trade, pricing feed or regulatory reporting convention.

Checked October 18, 2026 against the official TBILLYIELD help and official SDKJS source tagged v10.0.0.169. Desktop Editors 10.0 was released October 13, 2026. The original introduction version for this individual function is not established; current help does not mark it retired or deprecated.

All results in this guide are expected values from documentation, source inspection and independent arithmetic, not application observations. Neither the application nor its calculation engine was used to test these examples. The tag matches the installed version/build designation but does not establish identical behavior in every older release, mobile client, server deployment or imported workbook. Examples use English names and comma argument separators; adapt separators to editor settings. These fictional calculations explain a function, not an investment or borrowing recommendation.

• DATE
• DAYS