A month grouping can merge the same month across several years if the year is not represented. Check the pivot’s actual groups rather than relying on familiar month labels.
Confirm the source dates
Inspect whether the source column contains actual dates with the intended year, month, and day. Text dates or mixed types can prevent expected grouping or produce incomplete results.
Retain the original source while repairing imported dates. Do not convert uncertain dates solely to make the grouping control available.
Choose a year-aware grouping
In the pivot, right-click a date-formatted item and use Create pivot date group. Choose the appropriate period and inspect whether the resulting structure distinguishes years.
When necessary, use separate Year and Month grouping levels or a source helper containing each month’s actual first date. A displayed month-and-year key retains chronology more clearly than a month name alone.
Test across reporting boundaries
Include January from two years and records around December-to-January. Compare the pivot totals with a small independently grouped source sample. Confirm month order is chronological rather than alphabetical.
For timestamps, establish the reporting time zone before assigning calendar months. Fiscal periods may need a different helper key rather than ordinary calendar-month grouping. Review active filters and source-range growth as separate issues. If a month is missing, check whether there were no records, whether it was filtered out, or whether the source omitted it. Do not invent zero observations merely to fill a visual gap without documenting that reporting policy.
References
Reviewed against the linked official product guidance on November 3, 2026. Features, limits, screen labels, and access can vary by account, platform, region, and organization policy.