Date & Time
Custom 1-letter ("MTWRFSU") & 2-letter weekday abbreviations (WEEKDAY, MID & CHOOSE)
Map numeric dates to explicitly chosen one- or two-letter weekday labels, independently of localized weekday names.
Choose an explicit weekday-label convention
TEXT(date,"ddd") produces an abbreviated weekday name according to the engine and locale; it is not universally three characters. Taking the first character can produce collisions. Here the labels are deliberately fixed strings, not automatic translations.
WEEKDAY(date,2) gives Monday1 through Sunday7. MTWRFSU is a chosen convention with R for Thursday and U for Sunday, not a universal academic or airline standard. Explain the legend to readers or replace it with labels appropriate to the audience.
This exercise accepts numeric whole-day dates from March1,1900 through December31,9999. Text dates and fractional timestamps are rejected. Consistent workbook date-system interpretation is still required; hardcoded labels do not fix date conversion or time-zone issues.
| Calendar Date (A) | WEEKDAY(A, 2) | 1-Letter Academic Code | 2-Letter Gantt Code |
|---|---|---|---|
| 2026-10-26 (Mon) | 1 | "M" | "Mo" |
| 2026-10-29 (Thu) | 4 | "R" (Distinct from Tue "T"!) | "Th" |
| 2026-10-31 (Sat) | 6 | "S" | "Sa" |
| 2026-11-01 (Sun) | 7 | "U" (Distinct from Sat "S"!) | "Su" |
One-letter labels using an explicit MTWRFSU legend
Indexes 7-character string "MTWRFSU" at 1-based Monday..Sunday position.
=IF(ISNUMBER(A3),IF(OR(A3<DATE(1900,3,1),A3>DATE(9999,12,31),A3<>INT(A3)),"Invalid date",MID("MTWRFSU", WEEKDAY(A3, 2), 1)),"Invalid date")Locale-independent 2-letter (or custom language) code via CHOOSE
The output strings stay as written in the formula. Use translated strings when the desired display language changes.
=IF(ISNUMBER(A3),IF(OR(A3<DATE(1900,3,1),A3>DATE(9999,12,31),A3<>INT(A3)),"Invalid date",CHOOSE(WEEKDAY(A3, 2), "Mo", "Tu", "We", "Th", "Fr", "Sa", "Su")),"Invalid date")Try the example
Use the original values or change them to test your understanding.