that is if

USAGE SUMMARY

"that is if" is a perfectly acceptable phrase to use in written English.
It is used to make a conditional statement, i.e. something that will happen only if something else also happens. For example: "I will go to the party, that is if I'm feeling better by then."

✓ Grammatically correct

News & Media

Science

Academia

Wiki

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

That is, if he wants to.

The New York Times

That is, if it starts at all.

The New York Times

That is, if the weather cooperates.

The New York Times

That is, if the gambit is successful.

The New York Times

That is, if he could afford it.

The New York Times

That is, if it actually is cancer.

The New York Times - Health

That is, if divisions still exist.

The New York Times - Sports

That is, if it is ever used.

The Economist

That is, if Congress goes along.

The New York Times - Science

That is, if Congress lets it through.

The Economist

That is, if they ever did meet.

The New York Times

Expert writing Tips

Best practice

In journalistic writing, feel free to use it as a sentence fragment to emphasize the uncertainty of the preceding claim.

Common error

While using the phrase as a standalone fragment is common in media, avoid overusing this stylistic choice in highly academic or technical reports. In those cases, integrate it into a single sentence using a comma or semicolon to ensure a smoother, more formal transition.

Linguistic Context

The phrase "that is if" serves as a conditional clarifier or additive conjunction. According to Ludwig AI, it is primarily used to append a necessary condition to a previously stated fact or intention. In many examples, it functions as an appositive clause that restricts the scope of the main proposition.

Expression frequency: Very common

Frequent in

News & Media

75%

Science

10%

Academia

5%

Less common in

Wiki

5%

Formal & Business

3%

Social Media

2%

Ludwig's WRAP-UP

The phrase "that is if" is a versatile tool used across high-quality English sources to provide necessary context and conditions. Ludwig AI confirms its grammatical validity and its widespread use in both elite journalism and technical research. Whether you are using it to add dramatic emphasis to a news story or to define the limits of a scientific theory, it effectively bridges a claim with its required condition. To use it successfully, ensure that the following condition is clear and that the phrase's placement aligns with the desired tone of your writing, whether that be a punchy fragment or a smooth, integrated clause.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

provided that

Offers a more formal tone for setting conditions

assuming that

Focuses on the premise required for the main clause to be true

on the condition that

Uses more words to emphasize a strict requirement

supposing that

Introduces a more hypothetical or speculative condition

granted that

Used when conceding a point while setting a condition

so long as

Focuses on the duration or persistence of a condition

only if

Stronger and more restrictive than the original phrase

presuming that

Indicates an assumption is being made before the condition

in the event that

More formal and situational, often used in legal or technical contexts

if indeed

Adds an extra layer of skepticism to the condition

FAQs

How to use "that is if" in a sentence?

You can use "that is if" to add a condition to a statement, such as: "The team will win the championship, that is if they stay healthy."

What can I say instead of "that is if"?

Depending on the context, you can use alternatives like "provided that", "assuming that", or "on the condition that".

Is it correct to start a sentence with "that is if"?

Yes, it is common in journalistic and informal writing to start a new sentence with this phrase for emphasis, though in formal essays it is often better to attach it to the previous sentence with a comma.

What is the difference between "that is if" and "only if"?

While both introduce conditions, "only if" is more restrictive, implying that the outcome is impossible without that specific condition, whereas "that is if" often acts as a clarifying afterthought.