2.6 Dates and time arithmetic
Date maths gives you the answer you expected, including across financial years.
Before:01. Excel — First StepsUnlocks:03. Excel — Analysis
Excel stores every date as a plain number counting days, and every time as a fraction of one, and once that clicks, date arithmetic stops being mysterious. This topic covers TODAY, EOMONTH, EDATE, working-day calculations and ageing buckets — the stuff of deadlines and financial years. The great confusion is text that merely looks like a date: it sorts wrongly and refuses arithmetic while appearing perfectly normal, so real time is spent on spotting and converting it.
Work through these
How Excel stores dates and times as numbers
Dates are stored as numbers counted from a fixed starting point, and times are the fraction after the decimal. Once that clicks, date arithmetic stops feeling arbitrary.
TODAY, DATE, YEAR/MONTH/DAY, EOMONTH, EDATE
There are functions for today's date, for building a date from parts, and for taking parts out of one. Others move to month ends, or a set number of months away. These cover the majority of real date calculations.
Working days, ageing buckets and duration
Counting working days, sorting records into age bands, and measuring durations are the three date jobs that come up constantly in reporting. Each has a standard approach worth learning once.
Text that looks like a date, and how to convert it
A value that looks like a date but is stored as text will not sort or calculate, and it is extremely common in exported data. Converting it properly is the fix; retyping it is not.
Practice file
- xl-06-messy-data.xlsx
A deliberately horrible export: merged headers, blank rows, mixed date formats, stray text in number columns. The Power Query exercise.
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