that's why

USAGE SUMMARY

"that's why" is correct and usable in written English
You can use it to explain why a certain state of events has come to be. For example: "I ate too many sweets yesterday and now I have a stomachache - that's why I didn't make it to school today."

✓ Grammatically correct

News & Media

Academia

Science

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

That's why education programs are in English.

Procedia - Social and Behavioral Sciences

That's why we digitize.

Princeton University

That's why we're here.

Massachusetts Institute of Technology

That's why we exist.

Cornell University

That's why you're here!

Massachusetts Institute of Technology

That's why it is designed to withstand negative pressure loads.

Fusion Engineering and Design

"That's why it's disappointing".

The New York Times

That's why they're politics.

The New Yorker

That's why I watch.

The New York Times

That's why elections matter.

The New York Times

That's why galleries cluster.

The New York Times

Expert writing Tips

Best practice

Use "that's why" to clearly and directly state the cause-and-effect relationship between two events or situations.

Common error

Avoid overusing "that's why" in formal or academic writing; consider using more sophisticated causal connectors like "therefore", "consequently", or "as a result" to maintain a professional tone.

How to use

Learn how to use "that's why" with practical examples and tips.

How to use

Linguistic Context

The phrase "that's why" functions as a causal connector, linking a preceding statement or situation to its consequence or explanation. Ludwig AI confirms that "that's why" is correct and usable in written English, acting as a cohesive device to show cause-and-effect.

Expression frequency: Very common

Frequent in

News & Media

59%

Academia

20%

Science

14%

Less common in

Formal & Business

0%

Encyclopedias

0%

Wiki

0%

Ludwig's WRAP-UP

In summary, "that's why" is a versatile and commonly used causal connector that effectively links causes and effects. As Ludwig AI points out, it's grammatically sound and suitable for various contexts, though formal writing might benefit from more sophisticated alternatives. Its prevalence in news and media highlights its role in providing clear explanations. While "that's why" is helpful in many contexts, be mindful of the register and avoid overuse, particularly in more formal settings. The examples provided by Ludwig showcase its versatility and practicality in conveying causal relationships.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

that is the reason

Replaces the contraction "that's" with "that is" for a more formal tone.

that is why

Expands the contraction for clarity but maintains the same meaning.

therefore

Provides a single-word conjunction that indicates a logical conclusion.

consequently

Implies a result or effect following a cause.

as a result

Highlights the outcome of a preceding action or situation.

for this reason

Emphasizes the specific reason leading to a particular consequence.

this is the reason why

Adds emphasis and a more formal structure to the explanation.

that explains why

Focuses on the explanatory aspect of the cause-and-effect relationship.

this accounts for

Indicates that something provides a satisfactory explanation for something else.

hence

Offers a concise, slightly more formal way to introduce a consequence.

FAQs

How can I use "that's why" in a sentence?

Use "that's why" to connect a cause to its effect, such as, "I studied hard, "that's why" I passed the test".

What phrases are similar to "that's why"?

Similar phrases include "therefore", "consequently", "as a result", or "for this reason". Each can replace "that's why" depending on the context.

Is it okay to start a sentence with "that's why"?

While grammatically correct, starting a sentence with "that's why" can sometimes sound informal. In formal writing, consider rephrasing to maintain a more sophisticated tone.

What is the difference between "that's why" and "because"?

"That's why" introduces the effect or result, whereas "because" introduces the cause. For example, "I was late because of the traffic" (cause) versus "The traffic was bad, "that's why" I was late" (effect).