A technique for automatically determining new font sizes includes receiving information indicating a layout change for a document. The document includes a text frame that includes text content in a first font size. The text content covers a particular percentage of the text frame, and the layout change causes a change in the size of the text frame to a resized text frame. The technique includes determining a second font size for the text content in the resized text frame. A percentage of the resized text frame covered by the text content in the second font size is substantially similar to the particular percentage of the document. The method includes resizing the size of the text content from the first font size to the second font size and outputting a document with the resized text frame with the text content in the second font size.