You may add content using the Editor up to 32,000 characters per item. If you exceed that limit, you will be notified when you attempt to save, that you need to reduce the number of characters in the content you are attempting to add.
Typically, tables produce a large number of HTML characters. If you are adding a large table to a rich text field and find that the character limit has been exceeded, you may want to copy the "Source" to a tool such as Microsoft Word, which has a feature that measures the number of characters in selected text.
Prior versions of Workspace.com did not enforce a character limit on Editor content. If you have legacy data that exceeds the character limit, when you attempt to edit and save those items, you will be notified that the character limit is exceeded. If the limit is exceeded, copy the data in the Editor and paste it to Microsoft Word. Then select the pasted text, and copy it back to the Editor using the "Paste From Word" button on the Editor toolbar. The new version of the Editor included with Workspace.com reduces the number of HTML characters by approximately an 8:1 ratio. If the character limit is still being exceeded, you will need to reduce the size of the content, or split the content into two different items.