Daily DAX : Day 467 PREVIOUSWEEK

DAX Function: PREVIOUSWEEK

Purpose: Returns a table with all dates from the previous week (relative to the first date in the current context).

Syntax

PREVIOUSWEEK ( <Calendar> )

<Calendar> = reference to your date/calendar table (must be properly marked as date table or used in enhanced time intelligence mode)

Important Requirements

  • You need a proper Date / Calendar table
  • Best used with Enhanced DAX Time Intelligence (preview feature → now more widely available)
  • Usually combined with CALCULATE

Most Common Use Case

Compare this week vs previous week (week-over-week analysis)

Typical pattern – Previous Week Sales: 
Previous Week Sales = 
CALCULATE(
    [Total Sales],
    PREVIOUSWEEK( 'Calendar' )
)

Other useful variations:

-- Previous week margin %
Previous Week Margin % = 
DIVIDE(
    CALCULATE([Total Margin], PREVIOUSWEEK('Calendar')),
    CALCULATE([Total Sales],  PREVIOUSWEEK('Calendar'))
)

-- WoW % change
WoW Growth % = 
DIVIDE(
    [Total Sales] - [Previous Week Sales],
    [Previous Week Sales]
)

Typical Business Use Cases

  • Week-over-week sales / revenue comparison
  • Compare current week orders vs previous week
  • Monitor weekly active users / sign-ups
  • Week-to-date vs full previous week comparison
  • Retail / e-commerce performance tracking (very common)
  • Quick detection of sudden drops or spikes week-to-week

Quick Example Output (imagine calendar starting Monday)

Selected Date PREVIOUSWEEK returns dates...
2026-01-22 (Wed)2026-01-12 to 2026-01-18
2026-01-19 (Mon)2026-01-05 to 2026-01-11

Tip: If your week starts on Sunday or has a fiscal week definition → make sure your calendar table reflects that correctly.

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