When the DPI is changed in Windows (usually via the "Make text and other items larger or smaller" setting), it makes everything bigger or smaller - text, icons, the size of cells in Excel. The text "abcdefghi" fits neatly in a default sized cell at the default Calibri 11pt font. This is the same regardless of the DPI as while a higher DPI makes the text bigger, it also makes the cells in Excel bigger, so the same text still fits. There is a small discrepancy - I've found that you can fit a "j" on the end in some conditions.

When the DPI is set above 100%, NVDA seems to behave as if the text has got bigger but the size of the cell hasn't (just a guess). At 200%, I can about half fill a cell before NVDA announces it as overflowing (or cropped if there is text in the next cell). I tested this on Windows 10 with Excel 2016, and Windows 7 with Excel 2007.

To reproduce:

• Set "Make text and other items larger or smaller" to anything above 100% - the higher the value, the more obvious the effect.
• Sign out / back in.
• Open Excel
• Type text in a cell. The text "abcdefghi" fits in a cell at the default Calibri 11 under every condition I tried.
• Navigate away from the cell and back (tab then shift+tab). NVDA reads the text and reports "overflowing".