How long is a piece of string?

(British & Australian)

something that you say when someone asks you a question that you cannot answer about how big something is or how much time something will take 'So how long does a project like that take?' 'How long's a piece of string?'

Common Names:

Name	Pronounced	Usage
Aurora	ow-RO-rah (Spanish), ə-RAWR-ə (English), OW-ro-rah (Finnish)	Italian, Spanish, Portuguese, English, German, Romanian, Finnish, Roman Mythology
Ratnam	-	Indian, Telugu
Troy	TROI	English
Bittor	-	Basque
Honey	['hʌni]
Lenard	['leinɑ:t]