How long is a piece of string?
idiom
Used to suggest that there's no definite or answerable question about something, or it varies greatly.
How much longer will we have to wait? How long is a piece of string? I don't know the answer.

Often appears as...
- how much does it cost - how long is a piece of string?
- can you tell me - how long is a piece of string?
Usage tips
Informal
Idiomatic
idiom
Used to suggest that there's no definite or answerable question about something, or it varies greatly.
How much longer will we have to wait? How long is a piece of string? I don't know the answer.

Often appears as...
- how much does it cost - how long is a piece of string?
- can you tell me - how long is a piece of string?
Usage tips
Informal
Idiomatic
Definition 1 of 1

Uncertainty Context
Use when an exact number or amount cannot easily be given or is unknown.

How long will the meeting last? Well, how long is a piece of string?
Non-literal Use
Understand it's a rhetorical question, not expecting a literal answer about string.

How successful will the project be? That's like asking how long is a piece of string.
Avoid Overuse
Use sparingly to avoid vagueness in situations where specifics are important.

When budgeting, instead of asking 'How long is a piece of string?', seek exact figures.
Uncertainty Context
Use when an exact number or amount cannot easily be given or is unknown.

How long will the meeting last? Well, how long is a piece of string?
Non-literal Use
Understand it's a rhetorical question, not expecting a literal answer about string.

How successful will the project be? That's like asking how long is a piece of string.
Avoid Overuse
Use sparingly to avoid vagueness in situations where specifics are important.

When budgeting, instead of asking 'How long is a piece of string?', seek exact figures.
Uncertainty Context
Use when an exact number or amount cannot easily be given or is unknown.

How long will the meeting last? Well, how long is a piece of string?
Non-literal Use
Understand it's a rhetorical question, not expecting a literal answer about string.

How successful will the project be? That's like asking how long is a piece of string.
Avoid Overuse
Use sparingly to avoid vagueness in situations where specifics are important.

When budgeting, instead of asking 'How long is a piece of string?', seek exact figures.
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