Business letters: Reference line

On this page

• Purpose of reference line
• Format for reference line
• Placement of reference line
• Alternative to reference line
• Additional information

Purpose of reference line

The reference line is an optional letter part that gives the identification number of a file, invoice or other document related to the letter.

A reference line can make it easier to identify related documents, file correspondence or retrieve information at a later date.

Format for reference line

Begin the reference line with the word Re, followed by a colon and then the identifying information:

If there are two different reference numbers (one for the sender and another for the receiver), use two separate reference lines, and replace Re with Our reference and Your reference. The sender’s reference notation should come first and the receiver’s second, with a blank line between them:

Placement of reference line

Put the reference line at the left margin, on the second line below the date:

Note: The guideline above is for a letter in full block style. In modified block style, the reference line is placed on the same line as in full block style, but it begins at the centre of the page instead of at the left margin. For more information on different letter styles, see the article Business letters: Letter styles.

Alternative to reference line

You may omit the reference line and put the reference information in a subject line instead:

For information on where to place a subject line and how to format it, see the article Business letters: Subject line.

Additional information

• Correspondence and addresses – Guidelines and resources
• Business letters: Model letter in recommended format
• Business letters: Subject line