Completly vs. Completely: Which Spelling is Correct?

If you are looking for the correct spelling, here it is: Completely is the only correct spelling in standard English.

The word keeps the silent "e" from the base word "complete" before adding the suffix "-ly" (C-O-M-P-L-E-T-E-L-Y). Spelling it as "completly" is universally considered a grammatical error in professional, academic, and casual writing. If you struggle with this word, you are not alone—it is a frequently misspelled word because it defies common suffix spelling expectations.

Notice how the root "complete" ends in an "e", and the suffix "-ly" begins with an "l" (a consonant). To preserve the base spelling, the "e" is retained completely.

To understand why the "e" is kept, we have to look at standard English suffix rules. The word is built from the adjective "complete" and the adverb-forming suffix "-ly". When a root word ends in a silent "e", and you add a suffix that begins with a consonant, the silent "e" is almost always kept.

If we dropped the "e" (completly), it would visually sever the word from its root. By keeping the "e", the word flows naturally in writing: complete + ly = completely. This structural rule keeps the spelling aligned with similar words like "safely" (safe + ly) and "bravely" (brave + ly).

The root word "complete" comes from the Latin completus, the past participle of complere, meaning "to fill up." English adopted the word and simply attached the native adverb suffix "-ly" to describe doing something in a complete manner, preserving the original Latin root's spelling.

• Completely forgot
• Completely agree
• Completely different
• Completely destroyed
• Completely understand
• Completely sure

In daily conversation, "completely" is often used to emphasize an extreme state or absolute lack of something. For example, telling a friend, "I completely forgot" emphasizes that it wasn't a partial memory, but a total lapse. It is a standard intensifier in casual speech.

• I completely forgot to take out the trash this morning.
• She was completely exhausted after the long flight.
• We are completely out of milk and eggs.
• He completely changed his mind about the trip.
• The dog completely destroyed my favorite slippers.

In academic writing, "completely" is frequently used to describe the thoroughness of a process, the totality of a result, or the absolute absence of a variable. For instance, "The reaction completely eliminated the impurities." It denotes a 100% rate or state.

• The scientist completely disproved the old theory.
• The species was completely wiped out by the asteroid.
• The chemical reaction completely transformed the substance.
• The historical records were completely destroyed in the fire.
• The ecosystem has completely recovered from the oil spill.

In business emails, "completely" is useful for emphasizing certainty or finality. Saying "We completely revamped the system" sounds much more impactful than "We changed the system." It implies a thorough, comprehensive effort.

• The server was completely shut down for maintenance.
• We completely underestimated the cost of the project.
• The data was completely wiped from the hard drive.
• The report is completely accurate and ready for publication.
• He completely restructured the department to improve efficiency.