Shift by custom intervals across months, quarters, or years.
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PARALLELPERIOD shifts the date context by a fixed offset (e.g., -1 year, -3 months) and returns a parallel block of dates—not necessarily the same calendar day as the current cell. It is ideal for rolling windows and full prior-period totals.
Entire Previous Year Revenue =
CALCULATE(
[Total Revenue],
PARALLELPERIOD('Date'[Date], -1, YEAR)
)Assumes [Total Revenue] = SUM(Sales[Amount]) and the same Sales sample used in the SAMEPERIODLASTYEAR topic.
With a 2025 year slicer, compare [Revenue Last Year] (SAMEPERIODLASTYEAR) to [Entire Previous Year Revenue] (PARALLELPERIOD -1 YEAR):
Side-by-Side Behavior (2025 year filter)
| Month (2025) | Total Revenue | Revenue Last Year (SPLY) | Entire Previous Year Revenue |
|---|---|---|---|
| January | 1400 | 1200 | 3500 |
| February | 950 | 800 | 3500 |
| March | 1100 | 1500 | 3500 |
| Total | 3450 | 3500 | 3500 |
SAMEPERIODLASTYEAR vs PARALLELPERIOD
| Function | Grain | Typical Cell Value | Best For |
|---|---|---|---|
| SAMEPERIODLASTYEAR | Matches current period grain | Prior year for that row only (Jan → Jan) | YoY % by month, day, or quarter |
| PARALLELPERIOD | Shifts entire interval | Full prior year repeated on every row when year is filtered | Prior-year total banners, rolling 12M blocks |
With the report filtered to 2025, PARALLELPERIOD(..., -1, YEAR) evaluates revenue across all of 2024 ($3500 total) and applies that single result to every month row. SAMEPERIODLASTYEAR instead returns only the matching month from 2024—so February shows $800, not $3500. Choose PARALLELPERIOD when you need the entire shifted period; choose SAMEPERIODLASTYEAR when each row should align to the same calendar slice last year.