Double Consonants When a word ends in a single consonant, preceded by a single vowel, double the consonant before adding a suffix beginning with a vowel, but don't double when adding a suffix beginning with a consonant.
Ex:
... it's a two-syllable word with an accent on the last syllable followed by a suffix beginning with a vowel.
Ex:
Do not double the final consonant when adding a suffix beginning with a consonant. Examples..
some exceptions:
both canceled and cancelled are acceptable (weird, but true)