Which to use
“sustainable” is an adjective and “sustainably” is an adverb - they look or sound alike but fill different roles in a sentence.
- #5,271
- “sustainable” frequency rank
- #42,929
- “sustainably” frequency rank
- 48200
- confusion score
Side-by-Side Comparison
| Feature | sustainable | sustainably |
|---|---|---|
| Definition | Able to be sustained. | In a sustainable manner. |
Where the eye mixes sustainable and sustainably
Muted = shared; highlighted = the visual trap. They share 10 letters in sequence. sustainable and sustainably follow the identical consonant-vowel pattern (CVCCVVCVCCV). Same shape at a glance is often the real trap, independent of shared letters.
Visual trap between sustainable and sustainably
These two trip readers on the page rather than in the ear: sustainable is /səˈsteɪnəbəl/ while sustainably is /səˈsteɪ.nə.bli/. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - e in “sustainable” becomes y in “sustainably”, and the parts of speech differ too (adjective vs adverb), which is usually the fastest check. Our composite confusion score for this pair is 48200, derived from the frequency rank of both members and their visual similarity.
sustainable is recorded at frequency rank #5,271, classified as anadj, pronounced /səˈsteɪnəbəl/. sustainably is at rank #42,929, tagged as anadv, pronounced /səˈsteɪ.nə.bli/.
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 48200, this pair ranks #195,306 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of sustainable vs sustainably
Shared letters: abilnstu. Private to "sustainable": e. Private to "sustainably": y.
"sustainable" · 11 letters · shape CVCCVVCVCCV · "sustainably" · 11 letters · shape CVCCVVCVCCV
Known mistypes of this pair
- sustainable ← ssustainable · ssutainable · susatinable · susstainable · sustaianble · sustainabble · sustainabel · sustainablle
- sustainably ← ssustainably · ssutainably · susatinably · susstainably · sustaianbly · sustainabbly · sustainablly · sustainablyy
Frequently Asked Questions
Is swapping "sustainable" for "sustainably" ever safe?
In ordinary English text, does "sustainable" or "sustainably" show up more?
Useful next steps
Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.
- Full dictionary entry for "sustainable" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "sustainably" - compare definitions side by side with the headword page. Word entry
- This pair ranks #195,306 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes
Confusion rank #195,306 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.