Easyjet allows you to print your boarding pass at home for some flights.
However, the print preview always knocks off the tear off strip at the bottom, and you have to reset all your margins. I have tried to explain the problem to EJ but like many corporations they do not like feedback because they sense it will be negative, and so have FAQs and answers that don't deal with your problem, leaving you to contact them in ways that usually end with your pressing what is called the SUBMIT button, but which is probably a CLEAR MESSAGE button.
My guess is that the boarding pass page is formatted for the check- in desk printers which would print longer than A4, and they haven't bothered to think that we might not have such facilities at home.