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10.1 Current Date, Time, & Day-of-Week Functions: NOW, TODAY, & WEEKDAY

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1 Chapter 1: Exam Overview & MO-211 Fundamentals

1.1 MO-211 Exam Structure, Scoring, & Performance-Based Strategy 1.2 Excel Environment & Microsoft 365 Architecture

2 Chapter 2: Managing Workbooks & File Options

2.1 Workbook Versioning, AutoRecover, & File Properties 2.2 External Data Referencing & Cross-Workbook Formulas 2.3 Macro Security, Portability, & Workbook Distribution

3 Chapter 3: Workbook Protection & Collaboration Settings

3.1 Cell Locking, Range Permissions, & Worksheet Protection 3.2 Workbook Structure Protection & Editing Restrictions 3.3 Formula Calculation Options & Iterative Calculations

4 Chapter 4: Advanced Data Entry & Series

4.1 Flash Fill Patterns & Text Extraction Techniques 4.2 Advanced Fill Series (Linear, Growth, Date, & Step Configurations) 4.3 Dynamic Sequence & Random Data Generation (RANDARRAY, SEQUENCE)

5 Chapter 5: Custom Formatting & Data Validation

5.1 Custom Number Formatting Syntax & Masking Rules 5.2 Data Validation Criteria & Custom Formula Rules 5.3 Validation Input Messages, Error Alerts, & Data Circle Auditing

6 Chapter 6: Data Grouping, Summarization, & Cleansing

6.1 Data Grouping, Ungrouping, & Multi-Level Outlining 6.2 Subtotal Insertion & Summary Function Calculations 6.3 Duplicate Record Removal & Text-to-Columns Cleansing

7 Chapter 7: Advanced Conditional Formatting & Filtering

7.1 Formula-Based Conditional Formatting & Logical Tests 7.2 Data Bars, Color Scales, Icon Sets, & Rule Hierarchy 7.3 Advanced Filtering with Complex Criteria Ranges

8 Chapter 8: Logical Operations & Advanced Multi-Condition Functions

8.1 Nested IF, IFS, & SWITCH Logical Structures 8.2 Compound Boolean Logic: AND, OR, NOT, & XOR 8.3 Multi-Criteria Aggregations: SUMIFS, COUNTIFS, AVERAGEIFS, MAXIFS, & MINIFS

9 Chapter 9: Advanced Lookup Functions & Variable Optimization

9.1 Modern Lookups with XLOOKUP & XMATCH 9.2 Classic Matrix & Two-Way Lookups: INDEX & MATCH 9.3 Formula Optimization & Variable Assignment with LET

10 Chapter 10: Date, Time, Text, & Auditing Functions

10.1 Current Date, Time, & Day-of-Week Functions: NOW, TODAY, & WEEKDAY 10.2 Business Date Calculations: WORKDAY, NETWORKDAYS, EDATE, & EOMONTH 10.3 Modern Text Extraction & Array Splitting: TEXTSPLIT, TEXTJOIN, TEXTBEFORE, TEXTAFTER 10.4 Error Handling & Formula Auditing Tools

11 Chapter 11: Dynamic Array Functions & Spill Operations

11.1 Array Filtering & Extraction: FILTER Function 11.2 Multi-Level Sorting: SORT & SORTBY Functions 11.3 Deduplication & Sequence Arrays: UNIQUE & Array Reshaping

12 Chapter 12: Data Analysis, What-If Tools, & Financial Functions

12.1 Summarizing Multiple Ranges with the Consolidate Feature 12.2 What-If Analysis: Goal Seek & Scenario Manager 12.3 Financial Modeling Functions: PMT, NPER, & Forecast Logic

13 Chapter 13: Macro Automation & VBA Fundamentals

13.1 Recording Macros with Absolute vs. Relative References 13.2 Macro Storage, Shortcut Assignment, & Form Control Buttons 13.3 Managing & Modifying VBA Code in the Visual Basic Editor

14 Chapter 14: Advanced & Specialized Visualizations

14.1 Statistical Visualizations: Histograms & Pareto Charts 14.2 Hierarchy & Financial Visualizations: Waterfall, Funnel, Treemap, & Sunburst 14.3 Distribution & Multi-Axis Charts: Box & Whisker & Dual-Axis Combo Charts

15 Chapter 15: PivotTable Construction & Field Configuration

15.1 PivotTable Data Architecture, Layouts, & Style Configuration 15.2 Field Summarization, Number Formatting, & Custom Calculations 15.3 Value Display Modes: % of Total, Running Total, & Differences

16 Chapter 16: PivotTable Grouping, Slicers, & PivotCharts

16.1 Date & Numeric Field Grouping Strategies 16.2 Calculated Fields & Calculated Items in PivotTables 16.3 Slicers, Timelines, Report Connections, & PivotCharts

10.1 Current Date, Time, & Day-of-Week Functions: NOW, TODAY, & WEEKDAY

Key Takeaways Explain This Topic AI

Excel stores dates as whole-number serials counting from January 1, 1900 (serial 1) and stores time as the fractional remainder of a 24-hour day, so July 4, 2026 at noon is the number 46207.50.

TODAY() returns a date-only serial and NOW() returns a date-plus-time serial; both take empty parentheses and neither accepts an argument.

Both functions are volatile: they refresh on every recalculation event rather than ticking live, which is why a workbook containing them prompts to save on close even when nothing was typed.

Ctrl+; inserts a frozen date literal and Ctrl+Shift+; inserts a frozen time literal — the correct tools whenever a stamp must never change.

WEEKDAY(date, 2) numbers Monday as 1 through Sunday as 7, making =WEEKDAY(A2,2)>5 a reliable weekend test; the default return_type 1 starts at Sunday and misclassifies every Sunday.

Last updated: September 2026

Current Date, Time, & Day-of-Week Functions: NOW, TODAY, & WEEKDAY

Enterprise financial schedules, project management baselines, supply chain pipelines, and regulatory reporting calendars depend heavily on accurate temporal calculations. In Microsoft Excel, date and time arithmetic is governed by an internal serial numbering engine. Rather than treating calendar entries as arbitrary text strings, Excel converts every date and time into a precise numerical coordinate along a continuous timeline. Mastering that serial architecture — and the three functions MO-211 names for anchoring and classifying a single date, NOW , TODAY , and WEEKDAY — is the foundation for every business date formula that follows.

The 1900 Date Serial System & Fractional Time Architecture

By default, Excel for Windows and Excel for Microsoft 365 utilize the 1900 Date System . Under this system:

Whole Days as Integers : Day 1 corresponds to January 1, 1900 . Every subsequent calendar day increments this integer by exactly 1 . For example, July 4, 2026 corresponds to the serial number 46207 .

Time as Fractional Days : Time is stored as a decimal portion of a 24-hour day. Because one full day equals 1.0 , individual hours, minutes, and seconds are represented as fractions:

  • 1 Hour = 1 / 24 ≈ 0.041667 1 / 24 \approx 0.041667 1/24 ≈ 0.041667
  • 6:00 AM = 6 / 24 = 0.25 6 / 24 = 0.25 6/24 = 0.25
  • 12:00 PM (Noon) = 12 / 24 = 0.50 12 / 24 = 0.50 12/24 = 0.50
  • 6:00 PM = 18 / 24 = 0.75 18 / 24 = 0.75 18/24 = 0.75
  • 8 Hours (Standard Shift) = 8 / 24 = 1 / 3 ≈ 0.333333 8 / 24 = 1/3 \approx 0.333333 8/24 = 1/3 ≈ 0.333333

A combined date-time timestamp such as July 4, 2026, 12:00 PM is stored internally as the floating-point number 46207.50 . Adding 1 advances the timestamp by 24 hours, whereas adding 0.5 advances it by 12 hours.

Note

Historical Legacy Bug: Excel intentionally replicates a legacy Lotus 1-2-3 bug that treats the year 1900 as a leap year (recognizing February 29, 1900 as day 60), even though 1900 was not a leap year in the Gregorian calendar. This does not impact calculations for dates after March 1, 1900.

Volatile Current-Date Functions: NOW() & TODAY()

Every rolling report — aging schedules, days-past-due columns, tenure calculators, countdown dashboards — needs an anchor to "right now." Excel supplies two zero-argument functions for this, and MO-211 expects you to know precisely how they differ. =TODAY() // Current date only. Fractional (time) component is exactly 0.

=NOW() // Current date AND time, stored as a fractional serial.

  • Function Arguments Returns Example value on 4 July 2026 at 12:00 PM
  • TODAY() None (empty parentheses required) Whole-number date serial 46207
  • NOW() None (empty parentheses required) Date serial + time fraction 46207.50
  • Volatility: What It Actually Means

Both functions are volatile . A volatile function recalculates on every worksheet recalculation event — opening the file, editing any cell, pressing F9 , inserting a row, or sorting — not on a live ticking clock. NOW() therefore does not advance second by second while you watch it; it refreshes only when Excel next recalculates.

Two consequences the exam likes to probe:

Phantom "unsaved changes" : A workbook containing TODAY() or NOW() recalculates on open, marking the file dirty. Excel then prompts you to save on close even though you typed nothing.

Performance drag : Thousands of volatile cells force full-chain recalculation in large models. Compute the anchor once in a single helper cell and reference that cell everywhere else.

Volatile Function vs. Static Timestamp

When a value must be frozen — a signed approval date, an audit stamp — a formula is the wrong tool:

  • Requirement Correct technique Result
  • Date that rolls forward every day =TODAY() Recalculates; always current
  • Date that never changes Ctrl+; Hard-coded date literal
  • Time that never changes Ctrl+Shift+; Hard-coded time literal
  • Frozen date and time Ctrl+; then space then Ctrl+Shift+; Hard-coded timestamp
  • Practical Patterns =TODAY() - B2 // Days an invoice has been outstanding
  • =NOW() - TODAY() // Fractional time of day; format as [h]:mm
  • =EDATE(TODAY(), 3) // Same calendar day, three months out
  • =IF(TODAY() > C2, "Overdue", "Current")

Warning

NOW() and TODAY() return raw serials. In a cell formatted General , =NOW() displays 46207.5 rather than a timestamp. Apply a date or date-time number format before submitting an exam task.

Day-of-Week Classification: WEEKDAY()

WORKDAY moves a date across business days; WEEKDAY classifies a single date by its position within the week. It returns an integer, and the numbering scheme is controlled entirely by the optional second argument. =WEEKDAY(serial_number, [return_type])

Return-Type Numbering Schemes

  • return_type Numbering produced
  • 1 (or omitted) 1 = Sunday, 2 = Monday, … 7 = Saturday
  • 2 1 = Monday, 2 = Tuesday, … 7 = Sunday
  • 3 0 = Monday, 1 = Tuesday, … 6 = Sunday
  • 11 1 = Monday … 7 = Sunday
  • 12 1 = Tuesday … 7 = Monday
  • 13 1 = Wednesday … 7 = Tuesday
  • 14 1 = Thursday … 7 = Wednesday
  • 15 1 = Friday … 7 = Thursday
  • 16 1 = Saturday … 7 = Friday
  • 17 1 = Sunday … 7 = Saturday

Thursday, October 15, 2026 evaluated three ways: =WEEKDAY(DATE(2026,10,15)) // 5 (type 1: Sun=1, so Thursday is 5)

  • =WEEKDAY(DATE(2026,10,15), 2) // 4 (type 2: Mon=1, so Thursday is 4)
  • =WEEKDAY(DATE(2026,10,15), 3) // 3 (type 3: Mon=0, so Thursday is 3)
  • The Weekend Test — and Its Classic Trap

The standard weekend flag relies on return_type 2 , which pushes Saturday to 6 and Sunday to 7 so a single >5 comparison captures both: =IF(WEEKDAY(A2, 2) > 5, "Weekend", "Weekday")

Writing =WEEKDAY(A2) > 5 with the default type 1 is a silent failure: Sunday scores 1, so only Saturday (7) exceeds 5 and every Sunday is misclassified as a business day. The same rule powers a conditional formatting rule that shades weekend rows across A2:F200 (rule formula =WEEKDAY($A2, 2) > 5 , applied with column $A locked and the row relative), which is exactly how the two domains intersect on exam tasks.

WEEKDAY vs. WORKDAY: Choosing Correctly

  • Question being asked Function
  • "Is this date a weekend?" WEEKDAY
  • "Which day of the week is this?" WEEKDAY
  • "What date is 10 business days from here?" WORKDAY
  • "How many business days separate these dates?" NETWORKDAYS