Isabela P - What are the main differences between a business memo and a letter?

When aiming a management career, you are often going to be asked to write formal documents, such as memos and letters, in order to report and communicate with colleagues and other companies. What are the main differences between them?

Letters are usually addressed to someone outside the organization. They contain a more formal language and also background information, since the audience may not be familiar neither with the products/services that the company offers nor common information as someone within the organization. Most letters include a formal greeting (e.g. "Dear Sir"), and a closing statement that establishes a relationship between the reader and the writer (e.g. "look forward to working with you").

Memos are usually internal documents used to communicate information to coworkers, helping them to communicate without the need of time-consuming meetings. Memos are shorter in nature(usually 1 page long), and are less formal than letters, since the recipients usually have common knowledge of the issues and language used in the organization. Differently than letters, memos are usually not signed and do not start with a formal greeting, since they include the following pattern heading:

TO:
FROM:
DATE:
SUBJECT:


Reference: Dorbin, Sidney I., Christopher J. Keller and Christian R. Weisser. Technical Communication: In the Twenty-First Century. Upper Sadle, NJ. Pearson Prentice Hall, 2008.