Date & Time Functions Foundations

Date and time functions help Excel work with schedules, deadlines, reporting periods, and time-based calculations. Instead of treating a date like plain text, Excel stores it as a number that formulas can add, subtract, compare, and group.

That is why date formulas are so useful in practical work. A workbook can calculate overdue invoices, working-day deadlines, month-end dates, elapsed time, and weekly summaries without manual updates. Once the underlying dates are valid, the formulas become much more reliable than hand-typed text labels.

Main Function Groups

It helps to view this category as a few function groups rather than one long list. Some functions create valid dates and times, some extract one part from a date, some shift dates forward or backward, and others handle working-day logic. Once you know which group your task belongs to, the right formula is easier to choose.

These groups often connect in one workflow. For example, you might use DATEVALUE to convert imported text into a real date, YEAR to group it by year, and WORKDAY to calculate a follow-up deadline.

Why These Functions Matter

Date and time logic appears in many everyday spreadsheet tasks. A project plan may need working-day deadlines. A payroll sheet may need to count days between two dates. A dashboard may need the current month, current week, or today’s date to update automatically.

These functions also reduce manual maintenance. Instead of typing fresh dates every week or rebuilding schedules by hand, you can write formulas that keep adjusting as the source dates change. That makes reporting more consistent and much easier to maintain.

• They help you calculate deadlines, elapsed time, and reporting periods.
• They make schedules more reliable than manual date entry.
• They help group raw timestamps into usable calendar buckets.

Core Functions in This Category

This category starts with the date tools that appear most often in practical worksheets. They cover the main jobs: creating valid values, extracting components, shifting dates, and handling business-day logic.

• DATE / TIME for building valid date and time values.
• YEAR / MONTH / DAY for extracting date components.
• EDATE / EOMONTH for month-based movement and period boundaries.
• WORKDAY / NETWORKDAYS for business-day scheduling.
• WEEKDAY / WEEKNUM / ISOWEEKNUM for weekly grouping and calendar logic.

Starter Challenges

These three short challenges introduce three common patterns: returning the current date, extracting one part from a date, and building a working-day schedule.

Challenge 1 - Return Today’s Date

Start with TODAY(). It is one of the most common date functions because it keeps reports tied to the current day automatically.

=TODAY()

Challenge 2 - Extract the Year

Use YEAR when you need one part of a date for grouping, summaries, or filtering. This is a basic pattern that appears often in reporting.

=YEAR(B2)

Challenge 3 - Add Workdays

Use WORKDAY when a deadline should move by working days rather than by raw calendar days. This is much more practical for project and operations planning.

=WORKDAY(B3,5)

Once you understand these basics, the rest of the category becomes easier to follow because the functions mostly build on the same ideas: valid date values, extracted components, and reliable calendar logic.