Which to use
“efficiency” is a noun and “efficiently” is an adverb - they look or sound alike but fill different roles in a sentence.
- #3,749
- “efficiency” frequency rank
- #9,739
- “efficiently” frequency rank
- 13488
- confusion score
Side-by-Side Comparison
| Feature | efficiency | efficiently |
|---|---|---|
| Definition | The extent to which a resource is used for the intended purpose. | In an efficient manner. |
Where the spellings diverge
Shared letters are muted; the letters that actually set efficiency and efficiently apart are highlighted. They share 9 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
efficiency and efficiently form a confusable pair in the English index, two distinct headwords that are easily confused because they look alike, sound alike, or both. They differ by 1 letter(s) in length - close enough that the eye skips over the difference, far enough that meaning fully diverges. Our composite confusion score for this pair is 13488, derived from the frequency rank of both members and their visual similarity.
efficiency is recorded at frequency rank #3,749, classified as anoun, pronounced /ɪˈfɪʃ.ən.si/. efficiently is at rank #9,739, tagged as anadv.
Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.
With a confusion score of 13488, this pair ranks #475,487 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.
Frequency comparison
Frequently Asked Questions
Can "efficiency" and "efficiently" be used interchangeably?
Remembering efficiency vs efficiently
The fastest way to pick the right one every time.
- Check the role first: if you need a noun, it's “efficiency”; for an adverb, it's “efficiently”.
- See each word in full, definition, IPA, etymology and its other confusables. Full “efficiency” entry
- Browse more pairs most likely to be confused. Most confusable