Nature: Business letter is impersonal and universal in nature, personal letter is fully personal in nature
Purpose: Business letter is exchanging various business-related issues and information, personal letter is exchanging personal or family-related affairs and information
Scope: Business letter scope is wide and contains various types of business information, personal letter scope is limited and contains only personal information
Structure: Business letter follows officially recognized structure, personal letter does not follow any recognized structure
Formality: Business letter maintains formal rules and procedure, personal letter is informal
Size: Business letter generally is concise in size and avoids irrelevant matter, personal letter may be concise or large in size
Types: Business letter can be categorized differently, personal letter generally cannot be categorized
Salutation: Business letter salutation can be Sir, Dear Sir, Dear Mr. X, etc., personal letter salutations are Dear friends, my dear x, dear x, etc.
Language: Business letter language should be easy and simple, personal letter language may be easy, poetic, emotional, etc.
Copy: Business letter copy of business letter should always be preserved, personal letter copy of personal letter may or may not be preserved
Method: Business letter uses direct and persuasive method, personal letter uses only direct method