=left(A1,FIND(" ",A1)-1)

is more resilient as I understand some postcodes only have a trailing 2.

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HTH

Bob Phillips

"Helen" wrote in message
...
Anyone know how to trim a postcode of variable length, sometimes 5, 6 or 7
characters in length to remove the last 3 characters on the right hand
side
of the cell? The postcode is displayed with any gaps or marks and the
separator will varying but it is always the last 3 characters that are
superfluous.
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Thanks