Doubling final consonants

Doubling before vowels

We sometimes double the final consonant of a word before adding -ed, -er, -est, -ing, -able, -y (or any other ending that begins with a vowel).

• stop → stopped
• sit → sitting
• big → bigger

Which consonants are doubled?

We double the following letters:

Letter	Examples
b:	rub → rubbing
d:	sad → sadder
g:	big → bigger
l:	travel → travelling
m:	slim → slimming
n:	win → winnable
p:	stop → stopped
r:	prefer → preferred
t:	sit → sitting

We double final -s in gassing, gassed (but not usually in other words), final -z in quizzes, fezzes, and final -f in iffy (a colloquial word for ‘questionable’, ‘uncertain’).

Final w (in words like show, flow) is part of a vowel sound, and is not doubled.

• show → showing
• flow → flowed (not showwing, flowwed)

Only at the end of a word

We only double consonants that come at the end of a word. Compare:

• hop → hopping
• fat → fatter
• plan → planned
• but hope → hoping
• but late → later
• but phone → phoned

One consonant after one vowel letter

We only double when the word ends in one consonant after one vowel letter. Compare:

• fat → fatter
• bet → betting
• but fast → faster (not fastter)
• but beat → beating (not beatting)

Only stressed syllables

We only double consonants in stressed syllables. We do not double in longer words that end in unstressed syllables. Compare:

• upˈset → upˈsetting but ˈvisit → ˈvisiting
• beˈgin → beˈginning but ˈopen → ˈopening
• reˈfer → reˈferring but ˈoffer → ˈoffering

Note the spelling of these words:

• ˈgallop → ˈgalloping → ˈgalloped (not gallopping, gallopped)
• deˈvelop → deˈveloping → deˈveloped (not developping, developped)

Exception: final l in unstressed syllables

In British English, we double -l at the end of a word after one vowel letter in most cases, even in unstressed syllables.

• ˈtravel → ˈtravelling
• ˈequal → ˈequalled

In American English, words like this are most often spelt with one l: traveling.

Other exceptions

Consonants are sometimes doubled at the end of final syllables that are pronounced with full vowels (e.g. /æ/), even when these do not carry the main stress.

• ˈkidnap → ˈkidnapped
• ˈhandicap → ˈhandicapped
• ˈworship → ˈworshippers (AmE also ˈworshipers)
• ˈcombat → ˈcombating ˈ or combatting

Final -s is sometimes doubled in ˈ*focus(s)ing and ˈfocus(s)*ed.

Final c

Final -c changes to ck before -ed, -er, -ing, etc.

• picnic → picnickers
• panic → panicking
• mimic → mimicked

Why double?

The reason for doubling is to show that a vowel is still pronounced short. This is because, in the middle of a word, a stressed vowel letter before one consonant is usually pronounced as a long vowel or as a diphthong (double vowel). Compare:

• hoping /ˈhəʊpɪŋ/
• later /ˈleɪtə(r)/
• diner /ˈdaɪnə(r)/
• hopping /ˈhɒpɪŋ/
• latter /ˈlætə(r)/
• dinner /ˈdɪnə(r)/