✏️ WritingGrade 4Lesson 25
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Write Formal and Informal Letters

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Learning Objectives

  • 1Distinguish between the features of formal and informal letters
  • 2Write a letter using the correct format for the purpose and audience
  • 3Choose appropriate tone and language for formal versus informal contexts
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Mini Lesson

A letter is a written message sent from one person to another. The tone and format of a letter depend on your audience and purpose. Formal letters are used for official purposes; informal letters are written to people you know well.

Formal Letters

  • Used for business, applications, complaints, or official requests.
  • Begin with "Dear Mr./Ms. [Surname]:" and end with "Yours sincerely," or "Yours faithfully,".
  • Use polite, professional language — no contractions, slang, or casual expressions.
  • Include the sender's address, date, recipient's address, subject line, body, and signature.

Informal Letters

  • Written to friends, family, or people you know personally.
  • Begin with "Dear [First name]," and end with "Love," "Best wishes," or "Take care,".
  • Use a warm, relaxed tone — contractions, idioms, and friendly expressions are fine.
  • Structure is flexible: greeting, chatty paragraphs, and a warm closing.

Key Features to Compare

  • Formal: full sentences, no abbreviations, passive voice acceptable.
  • Informal: personal pronouns (I, you, we), short sentences, exclamation marks acceptable.
  • Both letters should have a clear purpose stated early in the body.
Formal vs Informal LettersA side-by-side table comparing formal and informal letters across greeting, tone, close, and what they are used for.Formal vs Informal LettersFormal LetterInformal LetterDear Mr./Ms. Surname:Professional, no contractionsYours sincerely,Business, complaint, requestDear [First name],Warm, casual, contractions OKLove, / Take care,Friends, family, pen palsGreetingToneCloseUsed forKey RuleMatch your tone to your audience and purposebefore you write a single word.
Two letter styles — same audience question.
Letter Structure ChecklistA seven-step checklist for letter structure: sender address with date, recipient address, subject line, greeting, body, sign-off, and printed name with signature.Letter Structure Checklist1. Sender address + Date2. Recipient address (formal only)3. Subject line (formal only)4. Greeting: Dear ... ,5. Body: Opening - Main point - Closing6. Sign-off: Yours sincerely / Love,7. Printed name + SignatureSteps 2 and 3 are formal only
A seven-part checklist for any letter you send.
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Tip: Before writing, ask "Who is my reader?" and "What is my purpose?" — your answers decide whether the letter is formal or informal.

Vocabulary
formal letter
A polite, official letter written in proper language.e.g. A letter to a town mayor is a formal letter.
informal letter
A friendly letter using everyday language.e.g. A letter to a cousin is an informal letter.
greeting
The opening line of a letter, like "Dear Mr. Lee".e.g. Choose a greeting that fits your audience.
closing
The polite ending of a letter before your name.e.g. "Yours sincerely" is a formal closing.
audience
The person who will read your letter.e.g. Match your tone to your audience.
tone
The feeling the writing creates, like polite or friendly.e.g. A formal letter has a serious tone.
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