Cost an arm and a leg is a common English idiom that means something is very expensive. It is usually used in casual conversations when a price feels unusually high.
This guide explains the meaning, grammar, usage, origin, synonyms, sentence examples, common mistakes, and American English use of the expression.
Quick Answer
“Cost an arm and a leg” means to be very expensive or cost a large amount of money. It is an informal, figurative English idiom.
TL;DR
- Cost an arm and a leg means very expensive.
- The expression is usually informal.
- It normally describes a high financial cost.
- Cost, pay, and charge can create related forms.
- The phrase is figurative, not literal.
- Its exact historical origin remains uncertain.
What Does “Cost an Arm and a Leg” Mean?
The idiom “cost an arm and a leg” means that something has a very high price. It can describe products, services, trips, repairs, housing, entertainment, or other purchases.
The expression is deliberately exaggerated. Someone saying it is not suggesting that actual body parts are exchanged for money.
Example:
“The new car costs an arm and a leg.”
This means the car is extremely expensive.
Is “Cost an Arm and a Leg” an Idiom?
Yes. “Cost an arm and a leg” is an idiom because its complete meaning is different from the literal meanings of its individual words.
The expression is also informal, so it is especially natural in conversation and casual writing.
Example:
“Those concert tickets cost an arm and a leg.”
The speaker means the tickets are very expensive.
How Do You Use “Cost an Arm and a Leg”?
The expression normally follows the thing being described as expensive. The verb cost changes according to the sentence’s tense.
Common patterns include:
- Present: This apartment costs an arm and a leg.
- Past: The repairs cost an arm and a leg.
- Future: The vacation will cost an arm and a leg.
- Present perfect: The renovation has cost an arm and a leg.
- Infinitive: It costs an arm and a leg to live downtown.
The phrase stays recognizable while the main verb changes.
“Cost an Arm and a Leg” Examples
Here are natural examples for everyday American English:
- That laptop cost an arm and a leg.
- The hotel costs an arm and a leg during the holidays.
- My car repairs ended up costing an arm and a leg.
- Those concert tickets cost an arm and a leg.
- Living in that neighborhood can cost an arm and a leg.
- The restaurant was excellent, but dinner cost an arm and a leg.
- Renovating an old house can cost an arm and a leg.
- That designer furniture costs an arm and a leg.
Cost, Pay, or Charge an Arm and a Leg?
These three verbs can shift the focus of the sentence.
Cost focuses on the price of something.
Pay focuses on the person spending money.
Charge focuses on the person or business asking for money.
Compare:
- The computer cost an arm and a leg.
- I paid an arm and a leg for the computer.
- The store charged me an arm and a leg for the computer.
A useful memory trick is:
Cost = price. Pay = buyer. Charge = seller.
Is “Cost an Arm and a Leg” Formal or Informal?
“Cost an arm and a leg” is informal English. It works well in conversations, casual emails, personal writing, and everyday storytelling.
For formal writing, a more direct expression may sound better.
Instead of:
The project will cost an arm and a leg.
You could write:
The project will be extremely expensive.
Or:
The project will require substantial funding.
Choose the wording according to your audience and purpose.
What Does “An Arm and a Leg” Mean?
In this expression, “an arm and a leg” refers figuratively to a very large amount of money.
The meaning comes from the complete expression and its surrounding verb.
For example:
- Cost an arm and a leg = be very expensive.
- Pay an arm and a leg = spend a very large amount.
- Charge an arm and a leg = ask for a very high price.
The phrase should normally be understood from context rather than literally.
Literal vs. Figurative Meaning
The expression is figurative. The words “arm” and “leg” are being used to create a strong image of an enormous sacrifice.
Compare these sentences:
- Literal: The athlete injured his leg.
- Figurative: The new equipment cost an arm and a leg.
- Literal: She raised her arm.
- Figurative: The vacation cost us an arm and a leg.
The second examples use the expression to describe money.
Synonyms for “Cost an Arm and a Leg”
You can use several alternatives when something is very expensive:
- Cost a fortune
- Cost a small fortune
- Be extremely expensive
- Be very costly
- Break the bank
- Cost a pretty penny
- Be pricey
- Be prohibitively expensive
- Set someone back a lot of money
- Be a major expense
The best choice depends on tone. “Cost a fortune” is common and direct, while “cost an arm and a leg” sounds more vivid and conversational.
Cost a Fortune vs. Cost an Arm and a Leg
Both expressions describe a high price, but their tone is slightly different.
“Cost a fortune” is straightforward and widely understood. “Cost an arm and a leg” is more colorful and exaggerated.
For example:
- “That house cost a fortune.” — direct
- “That house cost an arm and a leg.” — more vivid and conversational
Neither expression requires a specific dollar amount.
Common Mistakes With the Idiom
Learners sometimes remove articles or change the fixed wording.
- Correct: It cost an arm and a leg.
- Incorrect: It cost an arm and leg.
- Correct: The car will cost an arm and a leg.
- Incorrect: The car will cost arm and a leg.
- Correct: I paid an arm and a leg for it.
- Incorrect: I paid an arm and leg for it.
- Correct: They charged us an arm and a leg.
- Incorrect: They charged us arm and a leg.
Remember the established phrase as a complete expression.
Can You Use It in Formal Writing?
You can use an idiom in formal writing if the style permits conversational language. However, direct wording is usually clearer in academic or professional documents.
Consider these formal alternatives:
- The service is extremely expensive.
- The equipment has a very high purchase price.
- The project requires substantial funding.
- The proposed option would be prohibitively expensive.
The choice depends on the tone and purpose of your writing.
Where Did “Cost an Arm and a Leg” Come From?
The exact origin of “cost an arm and a leg” is uncertain. Several explanations have circulated, but they should not be treated as proven history.
One popular story claims that portrait painters charged more when paintings showed additional limbs. However, available evidence does not establish that story as the source of the idiom.
Dictionary.com discusses a possible connection with an older American expression involving “a leg,” while modern research places the figurative expression in American usage by the mid-20th century.
A documented 1949 example appeared in the Long Beach Independent. Because the historical evidence does not establish one certain origin, careful explanations should distinguish documented appearances from later theories.
American English Usage
The expression is well understood in American English and commonly appears in casual conversation.
People may use it when discussing:
- Housing
- Cars
- Travel
- Restaurants
- Repairs
- Electronics
- Entertainment
- Services
For example:
“The tickets were great, but they cost an arm and a leg.”
This sounds natural in casual American English.
Related English Idioms About High Prices
English has many expressions for expensive things.
- Cost a fortune — cost a very large amount.
- Break the bank — cost more than someone wants to spend.
- Cost a pretty penny — cost a significant amount.
- Be pricey — be relatively expensive.
- Set someone back — require a noticeable amount of money.
- Cost a small fortune — cost surprisingly much.
- Be prohibitively expensive — be too expensive for practical purchase.
- Cost the earth — a similar expression especially associated with British English.
These expressions are related, but their tone and regional use can differ.
How to Pronounce “Cost an Arm and a Leg”
A natural American English pronunciation gives the phrase a clear rhythm:
cost — an — arm — and — a — leg
The strongest stress normally falls on cost, arm, and leg.
When speaking naturally, the smaller words may sound less prominent. Listening to native speakers can help you copy the rhythm rather than saying every word with equal stress.
When Should You Avoid This Idiom?
Avoid the expression when you need highly formal or precise language.
For example, a financial report would usually benefit from a specific figure rather than a colorful idiom.
Use:
“The equipment costs $18,000.”
instead of:
“The equipment costs an arm and a leg.”
The idiom works best when you want to express reaction or emphasis, not exact financial information.
Quick Practice With “Cost an Arm and a Leg”
Complete each sentence with the correct form.
- The new phone ______ an arm and a leg.
- The repairs ______ us an arm and a leg last year.
- That hotel will ______ an arm and a leg.
- The company ______ us an arm and a leg for delivery.
- I ______ an arm and a leg for those tickets.
Answers:
- costs
- cost
- cost
- charged
- paid
The key is to match the verb with the subject and tense.
FAQs
What does “cost an arm and a leg” mean?
It means something is very expensive or requires a large amount of money. The expression is informal and figurative.
Is “cost an arm and a leg” an idiom?
Yes. It is an English idiom whose complete meaning is different from its literal words.
Is “cost an arm and a leg” formal?
No. It is generally considered informal. In professional or academic writing, “extremely expensive” may be clearer.
Can I say “pay an arm and a leg”?
Yes. “Pay an arm and a leg” emphasizes the person who spends the money.
Can I say “charge an arm and a leg”?
Yes. “Charge an arm and a leg” emphasizes the person or business asking for a high price.
What are synonyms for “cost an arm and a leg”?
Common alternatives include cost a fortune, break the bank, cost a pretty penny, and be extremely expensive.
Is the origin of the phrase known?
Not with certainty. Several theories exist, but the exact source remains disputed, so it is better to describe the origin cautiously.
Conclusion
Cost an arm and a leg means that something is very expensive. It is a colorful, informal idiom used frequently in everyday English.
Use it for conversational emphasis, but choose precise wording when writing formally or giving exact financial information. The best next step is to create a few original sentences using cost, pay, and charge.
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