Spelling Rules for adding the suffix -ing:
Rule 1 It’s easy add ‘ing’
Rule 2 If a one syllable word ends CVC (consonant vowel consonant)
Double the last letter, and add ‘ing’ (don’t double x, w or y)
Rule 3 If it ends in a silent ‘e’ drop the ‘e’ add ‘ing’
Rule 4 If it ends in ‘c’ add ‘k’ then ‘ing’
Rule 5 If the final syllable of a (multisyllabic) word is stressed
Then double the last letter and add the rest
Rule 6 If the final syllable of a (multisyllabic) word isn’t stressed
Don’t double the last letter add ‘ing’ instead
Rule 7 If a word ends with the letters ‘ie’
Change the ‘ie’ to a ‘y’ and add ‘ing’

British spellers will double the final ‘l’ of a multisyllabic word even when not stressed *
Spelling rules will always have exceptions *