PlanMaker WEEKDAY Function: Identify a Date’s Day of Week
Return weekday numbers from dates in PlanMaker, compare Sunday- and Monday-first modes, classify weekends and avoid Excel mode pitfalls.
Verification status: Official documentation referenced; example outcomes independently reasoned or arithmetically checked where stated. Not executed in SoftMaker PlanMaker 2026. How formula examples are checked
Quick answer: =WEEKDAY(DATE(2024,1,1),2) is expected to return 1, because January 1, 2024 was a Monday. The second argument controls which day is numbered first: a crucial detail when building work schedules, weekend alerts, or weekly reports.
Verification status: Official PlanMaker 2021, 2024 and 2026 documentation checked on 2026-10-12; calendar results independently verified. Not executed in SoftMaker PlanMaker or Excel. No genuine PlanMaker screenshots are included. Outputs below are expected, not observed application results.
What WEEKDAY does (and does not do)
WEEKDAY converts a date into a weekday number. It does not return a week number or a weekday name. A number without its associated numbering mode can be misleading: 1 means Sunday in default mode but Monday in mode 2. PlanMaker’s 2026 reference explicitly documents modes 1, 2 and 3.
Use it to flag weekend dates, filter Monday-start planning data, or turn a real date into a stable weekday key. For ISO week-of-year questions, use a different function such as ISOWEEKNUM or WEEKNUM. These functions answer a different question.
Official syntax, order and arguments
=WEEKDAY(Date [, Mode])
| Argument | Required? | Documented meaning | Important detail |
|---|---|---|---|
Date |
Yes | Date to classify; ideally a genuine date value or DATE(year,month,day) formula. |
Date-like strings can be interpreted differently across locales. |
Mode |
No | Select weekday numbering. | Omitted defaults to 1 (Sunday=1); documented values are 1, 2, 3. |
| Mode | Week begins with | Sunday | Monday | Saturday |
|---|---|---|---|---|
1 or omitted |
Sunday | 1 | 2 | 7 |
2 |
Monday | 7 | 1 | 6 |
3 |
Monday, zero-based | 6 | 0 | 5 |
The ordering is date, then mode. No additional PlanMaker modes are defined on its official 2026 reference page. Microsoft Excel’s WEEKDAY reference lists further return types 11–17; they should not be assumed supported in PlanMaker without native verification.
These formulas use the comma argument separator shown in the English reference. A localized installation may display or require a different separator, and date text such as 04/05/2024 is regional. Prefer the Function dialog and DATE(2024,5,4) where unambiguous input matters. SoftMaker explains entering dates as stored numbers in its data-entry documentation.
Reproducible worksheet: the same dates in three modes
Open a blank worksheet and enter headers in A1:D1: Date, Sunday=1, Monday=1, Monday=0. Type the following date formulas in A2:A7; in B2 enter =WEEKDAY(A2), C2 =WEEKDAY(A2,2) and D2 =WEEKDAY(A2,3), and fill B2:D2 through row 7. Format column A as dates if needed.
| Row | Formula in A | Calendar day | B expected | C expected | D expected |
|---|---|---|---|---|---|
| 2 | =DATE(1966,9,25) |
Sunday | 1 | 7 | 6 |
| 3 | =DATE(2024,1,1) |
Monday | 2 | 1 | 0 |
| 4 | =DATE(2024,2,29) |
Thursday | 5 | 4 | 3 |
| 5 | =DATE(2024,6,15) |
Saturday | 7 | 6 | 5 |
| 6 | =DATE(2024,12,31) |
Tuesday | 3 | 2 | 1 |
| 7 | =DATE(2025,1,1) |
Wednesday | 4 | 3 | 2 |
The first row reproduces SoftMaker’s documented WEEKDAY("09/25/1966") → 1 and WEEKDAY("09/25/1966",2) → 7 without relying on local text parsing. The rest are independently calculated calendar expectations; they have not been tested in PlanMaker.
Advanced applications
Identify Saturday and Sunday before scheduling
With a date in A2, type:
=IF(WEEKDAY(A2,2)>5,"Weekend","Weekday")
Mode 2 makes Saturday 6 and Sunday 7, so >5 catches both. With A2=DATE(2024,6,15), the expected text is Weekend; with A2=DATE(2024,6,17), it is Weekday. PlanMaker’s IF reference documents the IF branches separately. This formula classifies weekends; it does not exclude national holidays or company closures.
Convert to a Monday-first numeric weekday for weekly summaries
Use =WEEKDAY(A2,2) if a reporting worksheet needs a consistent integer from 1 for Monday to 7 for Sunday. For example, a value from =DATE(2024,6,16) produces the independently calculated result 7, while =DATE(2024,6,17) produces 1. If a zero-based index is needed instead, use =WEEKDAY(A2,3) (Monday 0, Sunday 6). Keep a descriptive heading such as Day of week (Monday=1) rather than assuming a number is a formatted weekday name.
Separate weekday from week-of-year
WEEKDAY(DATE(2024,12,30),2) gives 1 (Monday). By contrast, ISOWEEKNUM(DATE(2024,12,30)) gives 1, but that is week 1 of ISO year 2025, not a day of week. The identical numeral can describe two different things: name columns Weekday (Mon=1) and ISO week explicitly. See the PlanMaker ISOWEEKNUM documentation.
Troubleshooting and limits
| Symptom | Possible cause | What to check |
|---|---|---|
| Sunday displays 1 but your report expects 7 | Default mode used instead of mode 2. | Supply ,2, then document the week start. |
| Weekday is off by one in a Python or external dataset | External systems often use Monday=0. | Use PlanMaker mode 3 for Monday=0 to Sunday=6. |
| Formula input cannot be parsed | Local function separator or textual date format differs. | Build a date with DATE(...) and use PlanMaker’s function-insertion interface. |
| A number appears where a day name was expected | WEEKDAY is intentionally numeric. | Map 1–7 to labels separately, or use date formatting if appropriate. |
Unexpected result for Mode=11 |
Excel documents this mode; PlanMaker’s reference lists only 1–3. | Rework with mode 1, 2 or 3; test native behavior before relying on other modes. |
| Input is text rather than a stored date | CSV import may leave text unconverted. | Confirm the data type and parse it using explicit year/month/day components. |
| Date is before 1900 or after 2500 | Outside SoftMaker’s documented data-entry range. | Verify source values; do not assume a particular error message. |
Unverified edge cases: exact PlanMaker error codes for invalid dates, unsupported modes, blank cells, negative serials, and exported Excel workbooks are not asserted. The 2026 date input guide documents 1900-01-01 to 2500-12-31 as its date-entry range; that is not proof of a specific WEEKDAY out-of-range error.
PlanMaker version/platform and Excel comparison
The English 2021, 2024 and 2026 manuals all show the same core syntax and modes 1–3. This supports documentation coverage for those release families, not a native claim that every edition, operating system, NX subscription or free variant has been tested. Verify locally if deploying a workbook on a different product edition.
Excel also supports modes 1–3, using its return_type parameter, but it additionally documents 11–17. The date serial conventions differ by application, so share genuine date cells and test portability rather than comparing raw serial values. No cross-application workbook round trip was executed.
Official references and verification
- SoftMaker PlanMaker 2026 — WEEKDAY reference; checked 2026-10-12; exact syntax, modes and 1966 example.
- SoftMaker PlanMaker 2024 — WEEKDAY reference; checked 2026-10-12; matching documented syntax and modes.
- SoftMaker PlanMaker 2021 — WEEKDAY reference; checked 2026-10-12; matching documented syntax and modes.
- SoftMaker — Date input and stored dates; checked 2026-10-12; locale/date-entry notes.
- Microsoft Excel — WEEKDAY function; checked 2026-10-12; comparison of modes 1–3 and extra 11–17 (Excel only).
Verification status: Official documentation checked; calendar example outcomes independently calculated. Not executed in PlanMaker. No application screenshots were created or represented as genuine.