Maintain vs Sustain

When to use each in English, with meaning, register, and examples.

Maintain

Top 2,000 (common) B2 verb

Sustain

Top 2,000 (common) C1 verb

	Maintain	Sustain
Pronunciation	🇬🇧 //meɪnˈteɪn// 🇺🇸 //meɪnˈteɪn//	🇬🇧 /["/səˈsteɪn/","/səˈsteɪnz/","/səˈsteɪnd/","/səˈsteɪnɪŋ/"]/ 🇺🇸 /["/səˈsteɪn/","/səˈsteɪnz/","/səˈsteɪnd/","/səˈsteɪnɪŋ/"]/
Meaning	To keep something in good condition or continue to have it.	To keep something going or maintain it.
Example	To maintain a healthy lifestyle, you should exercise regularly.	We must find ways to sustain our natural resources for the future.
Register	Neutral	Neutral
How common	Top 2,000 (common)	Top 2,000 (common)
CEFR level	B2	C1
Part of speech	verb	verb
Collocations	maintain order, maintain balance, maintain standards, maintain equipment	no longer, barely, indefinitely, be able to, can, be unable to
Antonyms	neglect, abandon, discontinue	neglect, abandon, cease
Common mistakes	Confused with 'mainten' which is not a word., Using 'maintain' with uncountable nouns incorrectly., Omitting the object when using it in a sentence.	'Sustain' is often confused with 'sustained' as a past form., Learners sometimes forget to add an object after 'sustain'., 'Sustain' is misused when referring to temporary situations, instead of ongoing support.
Usage notes	Used in contexts involving care, upkeep, or support. Appropriate in both spoken and written English but varies from technical discussions to daily conversation.	Use 'sustain' in contexts about keeping something alive or supporting it over time. It can be formal when discussing topics like environmental issues or less formal in conversations about personal interests.

See it in real clips

Whether or not you can maintain loyalty.

Maintain

There's not a planet in our solar system that could sustain life...

Sherlock › S1 E1

Impossible to sustain a smoking habit in London these days.

There's not a planet in our solar system that could sustain life...

Sherlock › S1 E1

Impossible to sustain a smoking habit in London these days.

Sustain

Frequently asked questions: Maintain vs Sustain

What's the difference between Maintain and Sustain?

Maintain: To keep something in good condition or continue to have it. Sustain: To keep something going or maintain it.

Which is more advanced: Maintain and Sustain?

Sustain is the highest level, at C1, on the CEFR scale.

Are Maintain and Sustain the same CEFR level?

Maintain: B2, Sustain: C1 on the CEFR scale.

What part of speech are Maintain and Sustain?

Maintain: verb, Sustain: verb.

Can you show an example of each?

Maintain: To maintain a healthy lifestyle, you should exercise regularly. Sustain: We must find ways to sustain our natural resources for the future.

Can I use Maintain and Sustain interchangeably?

Not always. Maintain and Sustain are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.