Costly vs Expensive

When to use each in English, with meaning, register, and examples.

Costly

Top 2,000 (common) C1 adjective

Expensive

Top 1,000 (very common) A1 adjective

Most common: Expensive

	Costly	Expensive
Pronunciation	🇬🇧 /["/ˈkɒstli/"]/ 🇺🇸 /["/ˈkɔːstli/"]/	🇬🇧 //ɪkˈspɛnsɪv// 🇺🇸 //ɪkˈspɛnsɪv//
Meaning	Expensive; needing a lot of money.	Costing a lot of money.
Example	Buying new furniture may prove too costly.	This restaurant is too expensive for a casual dinner.
Register	Neutral	Neutral
How common	Top 2,000 (common)	Top 1,000 (very common)
CEFR level	C1	A1
Part of speech	adjective	adjective
Collocations	be, become, prove, extremely, fairly, very, for, in, in terms of, be, become, prove, extremely, fairly, very, for, in, in terms of	expensive taste, expensive hobby, expensive gift
Antonyms	inexpensive, cheap	cheap, affordable, inexpensive
Common mistakes	Confused with 'cost' which refers to the price itself., Used in a context where 'valuable' would be more appropriate., Assuming it only refers to money when it can also refer to high costs in other aspects, like time.	Confusing with 'costly', which has a similar but slightly different nuance., Using with a negative connotation inappropriately; 'expensive' is neutral., Incorrectly using 'expensive' in place of 'costly' in more formal contexts.
Usage notes	Use 'costly' to describe something that requires a lot of money, especially in a neutral or formal context. Avoid using it in very casual settings, where simpler words like 'expensive' might be preferred.	Used for items that cost more than average. Avoid using for inexpensive or cheap items.

See it in real clips

Sherlock › S1 E1

It's expensive, e-mail enabled, MP3 player.

Breaking Bad › S1 E7

This crap wasn't easy to get. And it's expensive.

Better Call Saul › S1 E1

Use only flowers that look expensive, but, you know, aren't.

Sherlock › S1 E1

It's expensive, e-mail enabled, MP3 player.

Breaking Bad › S1 E7

This crap wasn't easy to get. And it's expensive.

Expensive

Frequently asked questions: Costly vs Expensive

What's the difference between Costly and Expensive?

Costly: Expensive; needing a lot of money. Expensive: Costing a lot of money.

Which is more common: Costly and Expensive?

Expensive is the most common in everyday English.

Which is more advanced: Costly and Expensive?

Costly is the highest level, at C1, on the CEFR scale.

Are Costly and Expensive the same CEFR level?

Costly: C1, Expensive: A1 on the CEFR scale.

What part of speech are Costly and Expensive?

Costly: adjective, Expensive: adjective.

Can you show an example of each?

Costly: Buying new furniture may prove too costly. Expensive: This restaurant is too expensive for a casual dinner.

Can I use Costly and Expensive interchangeably?

Not always. Costly and Expensive are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.