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
it proved costly
Grammar usage guide and real-world examplesUSAGE SUMMARY
The phrase "it proved costly" is correct and usable in written English.
You can use it to indicate that something resulted in significant expenses or negative consequences after the fact. Example: "The decision to invest in that failing project proved costly for the company."
✓ Grammatically correct
News & Media
Alternative expressions(2)
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
31 human-written examples
It proved costly.
News & Media
It proved costly as Posh found an equaliser.
News & Media
Pietersen chose to go for his spinners and it proved costly.
News & Media
It proved costly as Arsenal doubled their lead on 42 minutes.
News & Media
Mr. Chandler decided to testify on his own behalf, and it proved costly.
News & Media
Woodson, who had used 10 or 11 players in games this season to limit their minutes, played only eight in his rotation Wednesday, and it proved costly.
News & Media
Human-verified similar examples from authoritative sources
Similar Expressions
29 human-written examples
The Toulon-bound player's interjection may have been instinct, but it still proved costly.
News & Media
It has proved costly and difficult to build pipelines from gas fields in western China, while liquefied natural gas for transport in ships is in short supply.
News & Media
Although the U.S. generally supports the group-aid idea, it has proved costly to some U.S. companies.
News & Media
But their early indiscipline gave Warrington a significant territorial advantage in the opening stages and it eventually proved costly as the Bulls were penalised near their own line, allowing Wolves scrum-half Myler to score the game's first try.
News & Media
But the Dodgers could never add any separation, allowing the Padres to hang around until it finally proved costly.
News & Media
Expert writing Tips
Best practice
Use "it proved costly" to succinctly convey that a past action or decision had negative consequences. This phrase is particularly effective when emphasizing the contrast between initial expectations and the eventual outcome.
Common error
Avoid using "it proved costly" when discussing potential or hypothetical scenarios. This phrase is best suited for describing events that have already occurred and demonstrably resulted in negative consequences.
Source & Trust
86%
Authority and reliability
4.5/5
Expert rating
Real-world application tested
Linguistic Context
The phrase "it proved costly" functions as a conclusive statement, highlighting the negative outcome or consequences that followed a particular action or decision. Ludwig AI confirms this through numerous examples where the phrase is used to denote an action's detrimental aftermath.
Frequent in
News & Media
87%
Formal & Business
7%
Academia
3%
Less common in
Science
2%
Encyclopedias
0%
Wiki
0%
Ludwig's WRAP-UP
The phrase "it proved costly" is a common and grammatically correct way to describe that a past action or decision had significant negative consequences. As evidenced by Ludwig AI, it's frequently used in news and media to report on events where decisions resulted in undesirable outcomes. The phrase maintains a neutral tone and is appropriate for formal writing. When using "it proved costly", ensure the context clearly indicates a past event with demonstrable negative results. Alternatives like "it turned out to be expensive" or "it had dire consequences" can be used for slight variations in meaning.
More alternative expressions(6)
Phrases that express similar concepts, ordered by semantic similarity:
it turned out to be expensive
Focuses specifically on financial expense rather than broader negative outcomes.
it proved to be disadvantageous
Highlights the unfavorable or detrimental nature of the outcome.
it ended up being a burden
Emphasizes the negative weight or difficulty caused by something.
it came at a great price
Emphasizes the high cost or sacrifice involved.
it led to unfavorable results
Highlights the undesirable outcomes following a specific situation.
it had dire consequences
Highlights severe and disastrous outcomes.
the repercussions were significant
Focuses on the importance and impact of the consequences.
it exacted a heavy toll
Suggests significant suffering or loss as a result.
it backfired spectacularly
Implies an unexpected and dramatic failure.
the fallout was considerable
Focuses on the widespread negative effects following an event.
FAQs
How can I use "it proved costly" in a sentence?
You can use "it proved costly" to describe a past decision or action that resulted in negative consequences. For example, "The company's decision to delay the marketing campaign "it proved costly" as competitors gained market share".
What are some alternatives to "it proved costly"?
Alternatives include "it turned out to be expensive", "it ended up being a burden", or "it had dire consequences" depending on the specific context.
Is it appropriate to use "it proved costly" in formal writing?
Yes, "it proved costly" is suitable for formal writing, particularly in news reports, analytical essays, and business documents. It conveys a clear and concise message about negative outcomes.
What is the difference between "it proved costly" and "it was expensive"?
"It was expensive" simply states a high cost, while "it proved costly" implies that something initially seemed acceptable but later resulted in negative or unforeseen expenses or consequences. The first focuses on an expected cost while the second focuses on an unexpected negative outcome.
Editing plus AI, all in one place.
Stop switching between tools. Your AI writing partner for everything—polishing proposals, crafting emails, finding the right tone.
Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Source & Trust
86%
Authority and reliability
4.5/5
Expert rating
Real-world application tested