Wrong font used for statement of purpose and résumé I used wrong font for my statement of purpose, rather than the one prescribed under the department’s specifications. Will this hamper my chances of admission into that university?
As far as I can tell, the reasons behind font prescriptions are usually:


To avoid silly or unreadable fonts such as Comic Sans or blackletter fonts.
To avoid biases.
To be able to quickly assess the character count of a document.
To prevent the circumvention of page limits or similar by using a narrow font or similar.


(Whether one should care about character counts or page limits to the extent that the last two points matter at all is another discussion.)

Now, the if rules were only made with these purposes in mind, they would be something like:


  The statement of purpose must be set in a traditional sans-serif font such as …


or if the restriction is due points 3. or 4.:


  The statement of purpose must be set in Arial, Helvetica, Liberation Sans, … or any metrically similar font (in 11 pt with double line spacing …)


Unfortunately, the people making these rules usually do not know sufficiently much about typography or are even aware of that not everybody has Arial and Times New Roman pre-installed on their computers. Similarly, some applicants may be confused by such instructions. Therefore you end up with prescriptions that just require a Arial or Times New Roman, though probably nobody really thinks that you must use those very fonts.



Thus to evaluate the impact of your font choice, you first have to find out for which reason the font prescription was made. To this purpose, ask yourself questions such as the following:


Are other aspects such as font size, linespacing and borders prescribed as well? If yes, the prescription is likely due to point 3 or 4.
Is there any prescription on the length by other means as the word or character count? If yes, it’s almost certainly point 4.
Is a wide variety of fonts offered? If yes, the description is probably due to point 1, perhaps 2.


Finally, you need to consider, how much your actual font choice sabotages this purpose. Some examples:


If Times New Roman was prescribed due to reason 1 and you chose another traditional serif font such as Georgia or Baskerville, it will likely be without consequences. Even, if you used a traditional sans-serif font, you might fare well, as whoever is reading your submission may not even be aware of the prescriptions in this case.
If Times New Roman was prescribed due to reason 4 and you used Liberation Serif, which was designed to be metrically equivalent (i.e., each character takes up the same space), this will likely be without consequences. You need to have a trained eye to even spot the differences between the two, if you are not specifically looking for them:


If you used Comic Sans and it was not the prescribed font, this will likely have disadvantages, no matter what the reasons behind the prescription are and even if there was no font prescription to begin with.


However, at the end of the day, you can only guess the intentions behind the prescriptions and your document may get into the hands of some pedantic who radically enforces for these rules for their own sake (especially, if submissions were to be made in a format that allows to easily control the used font). Thus, if you want to be sure, only time (or asking the university) can tell.