Accessible Excel (implementation guide)

4.3. Nested tables

Tables are not nested and do not contain split or merged cells.

What is meant by this?

In order to keep the data clear in Excel and enable correct allocation, each row should have the same number of columns. Connected or split cells can cause confusion as it is difficult to determine which column heading the content should be assigned to. Each cell should contain only one piece of information to allow easy ordering, filtering and analysing. It is therefore advisable not to split or merge cells in order to clearly structure and process the data.

Nested cells should be completely avoided in tables. Nested cells mean that a cell contains a separate table or another complex data structure. This leads to confusion and can cause problems when processing data in Excel, as Excel is not designed for such complex data structures.

Why is it important?

If table cells are merged, split or nested, this can lead to problems as the information can no longer be assigned to the corresponding column headings. This can lead to the information being interpreted incorrectly or incompletely, which can lead to errors or misunderstandings. This can happen in particular when the table is viewed enlarged. Users of screen readers and voice output also face challenges in correctly assigning and interpreting the cells when they are connected, split or nested. To avoid such problems, tables should be formatted in such a way that each cell can be assigned to a specific column and the information is easy to interpret.

How can I implement/check it?

To ensure that the cells in a table are not connected or separated, table cells should not be merged or separated. If it is necessary to place additional information in a cell, new rows or columns can be added for this purpose. However, it is important to ensure that each row has the same number of columns so that the content can be assigned to the correct column headings. If too much information is placed in a table, either the table should be split into several tables or an alternative display format should be selected.

To check whether your table contains nested, split or merged cells, please follow the steps below:

1. Visually check each cell in the table to ensure that no cell has been split into smaller parts and that no cells have been merged into a larger cell.
2. Make sure that each cell contains only one type of information and that no cell contains a complex data structure such as an embedded table or chart.
3. If you find nested, split or merged cells, separate or explode them to ensure that each cell contains only one clear and unambiguous piece of information.
4. Check the entire table to ensure that it is well structured and clear so that the data is easy to read and process.

If you find nested, split or merged cells in your Excel spreadsheet and want to explode them, please follow the corresponding steps:

Separation of cells:

1. To separate split cells, select the relevant cells, then right-click and select "Split cells".
2. Enter the desired number of cells in horizontal or vertical direction and confirm your selection.

Dissolve merged cells:

1. Select the merged cells, go to the "Start" tab and click on the "Merge cells" button (the option with an arrow that merges cells). This will return the cells to their original form.

Removal of nesting:

1. If you have data that is contained in nested cells or complex structures, it is advisable to place these in separate cells or tables to make the table clearer.