This kind of problem usually is caused by a setting Firefox picked up for your printer that is incorrect. You can clear out all the preferences for that printer as described in the following article, or try a shortcut first. ''Support article:'' [[Fix printing problems in Firefox]] ''Shortcut:'' '''''Firefox Using One Corner/Side of the Page''''' One reason for Firefox not to use your entire piece of paper is if it misread the printer data and thinks it holds very small paper. As a possible quick fix, try this: (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk. (2) In the search box above the list, type or paste '''paper_data''' and pause while the list is filtered (3) This value varies, but based on past threads: * 1 means letter size * 9 often means A4 size * 256 is an unknown small size that sometimes shows up on Brother printers for no apparent reason To edit a preference, double-click it to open an editing control. After modifying the value, press Enter or click the checkmark button to save. ''If Print Preview shows only one side of the paper being used:'' (4) In the search box above the list, type or paste '''paper_width''' and pause while the list is filtered (5) These preferences normally have a value of '''-1''', but you can manually override the default by changing this to '''8.5''' (for letter-sized paper) Any improvement?