Use popular fonts that are not overly decorative in order to ensure optimum scannability.
Following are some samples of good fonts for a scannable resume:
Serif Fonts (traditional fonts with little "feet" on the edges of the letters)
Sans Serif Fonts (contemporary fonts with no decorative "feet")
It doesn't make any difference whether you choose a serif or a sans serif font, but the font size should be no smaller than 9 points and no larger than 12 points for the text. Having said that, you will notice that the fonts in the examples above are all slightly different in size even though they are exactly the same point size. Every font has its own designer and its own personality, which means that no two typefaces are exactly the same.
The key to choosing a font for a scannable resume is that none of the letters touch one another at any time. This can be caused by poor font design, by adjusting the kerning (the spacing between letters) in your word processor, or by printing your resume with a low-quality printer (i.e., some dot matrix printers). Even some inkjet printers can cause the ink to run together between letters with the wrong kind of paper.
Any time one letter touches another, a scanner will have a difficult time distinguishing the shapes of the letters and you will end up with misspellings on your resume. A keyword search looks for words that are spelled correctly, so a misspelled word is as good as no word.
This is the same reason you don't want to use underlining on your resume. Underlines touch the descenders on letters like g, j, p, q, and y and make it difficult for an OCR program to interpret their shapes. Take a look at these words and see if you can tell where a scanner would have trouble:
Related to fonts are bullets--special characters used at the beginning of indented short sentences to call attention to individual items on a resume. These characters should be solid for a scannable resume. Scanners interpret hollow bullets as the letter "o." Avoid any unusually shaped bullets that a scanner might interpret as a letter.
While we are on the topic of special characters, the % and & signs in some fonts cause problems for OCR software because they look like letters of the alphabet, so always spell out the words percent and and. Foreign accents and letters that are not part of the English alphabet will also be misinterpreted by optical character recognition.
Even though you have probably heard that italics are a no-no on a scannable resume, today's more sophisticated optical character recognition software can usually read italics without difficulty (provided the letters don't touch one another!). The experts at Resumix and SmartSearch2 all state that their software has no problem reading italics, and my staff has confirmed that with tests. We have even scanned resumes typeset in all italics without a problem, although I don't recommend serif italics simply from a readability standpoint. The exception, of course, are those italic fonts where one letter touches another. The key is to choose a font that is easy to read and not overly decorative.