1. Blank Rows Split the Data Range
If there is a blank row inside the dataset, Excel may treat rows below it as a separate block. Remove unnecessary blank rows or convert the range to a table with Ctrl + T.
2. The Filter Range Is Too Small
Click a filtered header and check whether the selected range covers all rows. If new rows were added below the original range, they may not be included in the filter.
3. Rows Are Hidden Manually
Filters and manually hidden rows can overlap. Clear all filters, unhide rows, and apply the filter again.
4. Merged Cells Break Filtering
Merged cells make filtering and sorting less predictable. Unmerge cells in the dataset and fill repeated values down where needed.
5. Data Types Are Mixed
Numbers stored as text, dates stored as text, and values with extra spaces may appear under unexpected filter groups. Clean the data before relying on the filter results.
Helpful Tools
Use Remove Blank Rows to clean broken ranges, Sort Excel to test the cleaned range, and Column Statistics to find blanks and unusual values.