Used and loved by millions
Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.

Justyna Jupowicz-Kozak
CEO of Professional Science Editing for Scientists @ prosciediting.com
that's the key
Grammar usage guide and real-world examplesUSAGE SUMMARY
"That's the key" is a correct and usable phrase in written English.
You can use it when you want to emphasize the importance of something or to draw attention to a point. For example: "Finding a way to motivate the team is essential - that's the key."
✓ Grammatically correct
News & Media
Alternative expressions(20)
that's the heart of the matter
that's the signal
that's the impression
It seemed that way to me
I got that impression
That was my understanding
I got the impression
I understood that
I inferred that
I sensed that
I gathered as much
I concluded that
I perceived that
it gave me that idea
i thought so
seemed like that
I had that feeling
That's what I took away
it was my understanding
that was my understanding
Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Human-verified examples from authoritative sources
Exact Expressions
58 human-written examples
Adaptability, that's the key.
News & Media
That's the key to Bloomberg's success.
News & Media
That's the key thing".
News & Media
That's the key.
News & Media
That's the key point.
News & Media
"That's the key test".
News & Media
That's the key question".
News & Media
"That's the key intervention point.
News & Media
"That's the key to it.
News & Media
That's the key piece there".
News & Media
"That's the key benefit.
News & Media
Expert writing Tips
Best practice
When using "that's the key", ensure the context clearly establishes what "that" refers to. Ambiguity can weaken the impact of your statement. For example, instead of saying "Adaptability, that's the key", you could say "Adaptability is the key to success in a rapidly changing environment."
Common error
Avoid using "that's the key" excessively in formal writing or presentations. While the phrase is grammatically correct, overuse can make your writing sound repetitive or simplistic. Consider using more sophisticated synonyms like "the crucial element" or "the pivotal factor" to maintain a professional tone.
Source & Trust
89%
Authority and reliability
4.5/5
Expert rating
Real-world application tested
Linguistic Context
The phrase "that's the key" functions as a sentence fragment or a short declarative statement used to emphasize the crucial element or point being discussed. Ludwig AI confirms this usage is prevalent across various contexts, highlighting its role in drawing attention to significant details.
Frequent in
News & Media
98%
Formal & Business
1%
Science
1%
Less common in
Wiki
0%
Encyclopedias
0%
Reference
0%
Ludwig's WRAP-UP
In summary, "that's the key" is a grammatically sound and frequently used phrase that serves to emphasize a crucial element or point. Ludwig AI affirms its widespread applicability across various contexts. It functions as a short declarative statement, guiding attention to significant details. While versatile, it's essential to ensure the context clearly defines what "that" refers to, and overusing it in formal settings should be avoided. Numerous alternatives, such as "that's the crux" or "that's the essential point", can add variety to your writing.
More alternative expressions(10)
Phrases that express similar concepts, ordered by semantic similarity:
that's the crux
Replaces "key" with "crux", highlighting the most important or decisive point.
that's the heart of the matter
Emphasizes that the identified element is central to the issue being discussed.
that's the critical factor
Substitutes "key" with "critical factor", stressing the importance of a specific element for success.
that's the essential point
Uses "essential point" to convey that something is fundamental and necessary.
that's the crucial aspect
Highlights the significance of a particular aspect, making it vital for consideration.
that's what really matters
Focuses on the element that holds the most importance or significance in the situation.
that's the secret ingredient
Implies that a particular element is the hidden, vital component for success or understanding.
that's the linchpin
Uses "linchpin" to describe the element that holds everything together or is essential for stability.
that's where the magic happens
Figuratively emphasizes the place or action where the desired result is achieved.
that's the golden rule
Indicates a fundamental principle that should always be followed to achieve success.
FAQs
How can I use "that's the key" in a sentence?
You can use "that's the key" to highlight the most important aspect of something. For instance, "Understanding the customer's needs; "that's the key" to successful marketing".
What are some alternatives to saying "that's the key"?
Alternatives include phrases like "that's the crux", "that's the essential point", or "that's the critical factor", depending on the context.
Is it grammatically correct to say "that's the key"?
Yes, "that's the key" is grammatically correct and widely used in spoken and written English to emphasize a crucial element or point.
What is the difference between "that's the key" and "that's the main point"?
"That's the key" emphasizes the crucial element needed for success or understanding, while "that's the main point" simply highlights the central idea being discussed. The former implies more importance or necessity.
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Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Source & Trust
89%
Authority and reliability
4.5/5
Expert rating
Real-world application tested