In a one-syllable verb ending in one consonant letter preceded by one vowel letter, double the final consonant letter (never double "w, x, y").
beg begging begged blur blurring blurred flip flipping flipped plan planning planned stop stopping stopped thin thinning thinned rub rubbing rubbed split splitting (split) step stepping stepped stir stirring stirred swim swimming (swam, swum) tap tapping tapped wrap wrapping wrapped fix fixing fixed play playing played plow plowing plowed
If the verb ends with "e", drop "e", then add "ing" or "ed". Do not double the consonant letter.
come coming (come, came) date dating dated dine dining dined hide hiding (hid, hidden) hope hoping hoped injure injuring injured ride riding (rode, ridden) slide sliding slid smile smiling smiled type typing typed write writing (wrote, written)
If a verb has two vowel letters before the final consonant letter, do not double the consonant letter.
bleed bleeding (bled) eat eating (ate; eaten) rain raining rained ruin ruining ruined seat seating seated fool fooling fooled dream dreaming dreamed/dreamt feel feeling felt
When a verb ends with "y", and before "y", it's a consonant, change "y" to "i", and then add "ed". (Never double "y, x, w")
carry carrying carried dry drying dried fry frying fried fly flying (flew; flown) reply replying replied study studying studied try trying tried worry worrying worried
When a verb ends with "y" and before "y" there is only one vowel letter, do not change "y" to "i"; simply add "ing" or "ed".
buy buying (bought) employ employing employed enjoy enjoying enjoyed play playing played pray praying prayed stay staying stayed
For a two-syllable or three-syllable verb, if the last syllable is stressed, follow the one-syllable word spelling rule to double the final consonant letter.
acquit acquitting acquitted admit admitting admitted begin beginning (began, begun) commit committing committed control controlling controlled deter deterring deterred excel excelling excelled occur occurring occurred prefer preferring preferred refer referring referred submit submitting submitted transfer transferring transferred
If the last syllable is not stressed, do not double the final consonant letter.
budget budgeting budgeted benefit benefiting benefited cancel canceling canceled (US) counsel counseling counseled happen happening happened listen listening listened marvel marveling marveled offer offering offered open opening opened quarrel quarreling quarreled ripen ripening ripened visit visiting visited travel traveling traveled (US) vomit vomiting vomited worship worshiping worshiped (US)
There are some exceptions.
quit quitting (quit) debut debuting debuted exit exiting exited tie tying tied die dying died lie lying lied
