Idiom B2

The devil is in the details

Used to say the small details of a plan are the hardest part and can cause big problems

Pedagogically reviewed by LexFizz Team

Quick answer: “The devil is in the details” means used to say that the small details of a plan or project are often the most difficult part, and that overlooked details can cause serious problems.

Meaning

The devil is in the details — Used to say that the small details of a plan or project are often the most difficult part, and that overlooked details can cause serious problems.

Origin & History

This phrase is a modern variant of the older expression “God is in the details,” a saying associated with careful attention to craftsmanship and design, sometimes linked to architects and designers of the 19th and 20th centuries.

The “devil” version emphasises hidden difficulty rather than aesthetic care: it warns that a plan which looks simple on the surface can conceal small, troublesome details that cause it to fail if they are not addressed carefully.

Example Sentences

SentenceContext
The contract looked simple, but the devil is in the details.Legal, contracts
Everyone agreed with the plan in general, but the devil is in the details.Project planning
Before signing, read every clause carefully — the devil is in the details.Advice, caution
The project seemed straightforward until we discovered the devil is in the details.Business, project management
Negotiators spent weeks on the small print, proving the devil is in the details.Negotiation

How to Use It

This idiom is generally used to describe the situation directly, often following a form of the verb "to be" or paired with a verb of change such as "go" or "get." It works well in both spoken and written English, and is most effective when it clearly refers to a real, specific situation rather than being used vaguely.

Common Mistakes

Mistakes to Avoid

The devil is in the detail's.

The devil is in the details. — no apostrophe — it is simply the plural noun 'details'.

The devil was on the details.

The devil is in the details. — the preposition is 'in', not 'on'.

The devils are in the details.

The devil is in the details. — 'devil' is singular in this fixed phrase.

Similar Idioms

Practise This Idiom

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Quick Check: The devil is in the details

2 questions — test what you just learned.

1. What does “The devil is in the details” mean?

2. Complete the sentence: “The contract looked simple, but _____.”

Frequently Asked Questions

What does “The devil is in the details” mean?

“The devil is in the details” means Used to say that the small details of a plan or project are often the most difficult part, and that overlooked details can cause serious problems.

Where does the idiom “The devil is in the details” come from?

This phrase is a modern variant of the older expression “God is in the details,” a saying associated with careful attention to craftsmanship and design, sometimes linked to architects and designers of the 19th and 20th centuries.

Can you give an example of “The devil is in the details” in a sentence?

Here is an example: “The contract looked simple, but the devil is in the details.” — used in the context of legal, contracts.

Is “The devil is in the details” formal or informal?

This idiom is neutral. It is common in everyday speech, journalism, and semi-formal writing, though it is generally avoided in strict formal or academic writing.

What CEFR level is “The devil is in the details”?

This idiom is typically taught at B2 level. It is a common upper-intermediate expression that appears in conversation, journalism, and general writing, and learners at this level should understand and be able to use it actively.

What are common mistakes with “The devil is in the details”?

A common mistake is: The devil is in the detail's. The correct form is: The devil is in the details. (no apostrophe — it is simply the plural noun 'details')

What idioms are similar to “The devil is in the details”?

Similar idioms include: The proof is in the pudding, Read the small print, Measure twice, cut once, Every cloud has a silver lining. These share a related meaning or usage context.

How do I practise idioms like “The devil is in the details”?

Use LexFizz's Flash Cards and Flip Tiles exercises. Try writing your own example sentences using the idiom in context, and listen for it in films, podcasts, and everyday conversation.

Can “The devil is in the details” be used in writing?

Yes. It works well in informal writing, emails, and journalism. In everyday and semi-formal writing it is a natural and clear choice.

Does “The devil is in the details” have the same meaning in British and American English?

Yes, “The devil is in the details” is understood in both British and American English with the same meaning: Used to say that the small details of a plan or project are often the most difficult part, and that overlooked details can cause serious problems. The idiom is widely recognised across all major varieties of English.