Spelling: When to double the final consonant before a suffix

On this page

• General information
• Suffixes starting with a consonant
• Suffixes starting with a vowel
  • Words with one syllable
  • Words with two or more syllables
• Additional information

General information

The rules for doubling the final consonant of a word before a suffix depend on several factors, including how many syllables are in the root word, which letters the root word ends with and which letter the suffix begins with. The guidelines below will help you decide when to double the final consonant of the root word. Note, however, that there are exceptions to every rule. When in doubt, check a reliable Canadian dictionary.

Suffixes starting with a consonant

Do not double the final consonant of the root word if the suffix begins with a consonant:

• clock: clockwise
• commit: commitment
• correct: correctness
• delight: delightful
• direct: directly
• down: downward
• regard: regardless

Suffixes starting with a vowel

The rules for doubling the final consonant of a word before a suffix that begins with a vowel differ according to the number of syllables in the root word.

Words with one syllable

Double the final consonant before the suffix if all the of following conditions are met:

• the root word has only one syllable
• the last three letters of the root word are a consonant, a vowel and a consonant (you can use the mnemonic CVC)
• the root word doesn’t end in w, x or y
• the suffix is -y or begins with a vowel

Here are some examples:

• dip: dipped
• fat: fatty
• fit: fitted
• flit: flitting
• gel: gelled
• gum: gummy
• hot: hottest
• log: logged
• mad: madden
• rot: rotted
• scrub: scrubbing
• sit: sitting
• stop: stopping

Words with two or more syllables

Double the final consonant if all of the following conditions are met:

• the root word has more than one syllable
• the root word ends in a single consonant preceded by a single vowel
• the root word doesn’t end in w, x or y
• the stress falls on the last syllable of the root word
• the suffix begins with a vowel

Here are some examples:

• acquit: acquittal
• commit: committal
• occur: occurrence
• regret: regretted
• transmit: transmitted

For words that end in l, double the l before the suffix if all of the following conditions are met:

• the root word has more than one syllable
• the root word ends in a single consonant preceded by a single vowel
• the suffix begins with a vowel

Here are some examples:

• cancel: cancelled
• funnel: funnelling
• pencil: pencilling
• rebel: rebellion
• towel: towelled
• travel: traveller

Note: In Canada, the preference is to double the final l in the root word. However, while the form with the single consonant is much more common in the United States, it may also be accepted in Canadian spelling. When in doubt, check a reliable Canadian dictionary.

Additional information

• The final consonant before a vowel: When to double it (quiz)
• Spelling: International variations
• Spelling: Words ending in “c”
• Spelling: Words ending in “-ise” and “-ize”