Difference Between Formal and Informal Letter (with Examples)

The main difference between formal and informal letter writing lies in the reader and the purpose. A formal letter goes to an official, company, principal or editor for a work-related purpose; it has a subject line, a fixed layout, polite and impersonal language and closings such as “Yours faithfully”. An informal letter goes to a friend or relative; it has no subject, uses a warm, personal tone and closes with phrases such as “Your loving friend”.

This guide explains the differences in a 12-point table, compares the formats side by side, shows two examples on the same topic and ends with a short quiz.

Key Takeaways

• Formal letters have a subject line; informal letters do not.
• Formal letters include the receiver’s address; informal letters usually do not.
• Formal greetings: “Sir/Madam” or “Dear Mr. Rao”. Informal: “Dear Riya”.
• Formal closings: “Yours faithfully” or “Yours sincerely”. Informal: “Your loving friend”.
• Formal language is precise and impersonal; informal language is friendly and personal.

Difference Between Formal and Informal Letter: 12 Points

Formats Side by Side

Greetings and closings

Same Topic, Two Letters

The best way to see the difference between formal and informal letter writing is to compare two letters about the same event. Both below are about a science exhibition.

Formal: request to the principal

Informal: news to a friend

Language: Formal vs Informal

Word choice is another clear difference between formal and informal letter writing. Compare these pairs.

Why the Difference Matters

Knowing the difference between formal and informal letter writing helps in exams and in daily life. In exams, format carries a mark of its own, so a subject line in a letter to a friend, or a missing receiver’s address in a complaint, costs marks. In real life, the wrong tone can create a poor impression. For example, a casual message to a bank manager may be ignored, while a stiff, formal letter to a grandparent feels cold.

Therefore, think about your reader first. If the reader is an official or someone you do not know personally, choose the formal style. If the reader is a friend or family member, choose the informal style. However, some letters sit in between, such as a thank-you note to a teacher. In such cases, keep the formal layout but allow a warmer tone.

Semi-Formal Letters

Semi-formal letters go to people you know but who hold a position, such as a teacher, a neighbour or a family friend. They use the reader’s name, a polite but friendly tone and closings such as “Yours sincerely” or “With best wishes”.

Checklist Before You Write

1. Who is the reader? Decide formal, semi-formal or informal.
2. Do I need a subject? Yes for formal letters; no for informal ones.
3. Which greeting fits? Match it with the closing using the table above.
4. Is the tone right? Remove slang from formal letters and stiffness from informal ones.
5. Have I checked the difference between formal and informal letter layouts? Compare your draft with the side-by-side format table.

Types of Each Letter

Formal and Informal Letters in Exams

Check your board’s latest sample paper, because question choices can change each year.

Quick Quiz

Decide whether each letter should be formal or informal. Answers are below the list.

1. A letter to your cousin describing your new school.
2. A letter to the bank manager to update your mobile number.
3. A letter to your grandmother thanking her for a birthday gift.
4. A letter to the editor about stray dogs.
5. A letter to a company about a damaged parcel.
6. A letter to your friend inviting him to a cricket match.

Answers: 1 informal, 2 formal, 3 informal, 4 formal, 5 formal, 6 informal.

Common Mistakes

Students who confuse the difference between formal and informal letter styles often make these slips.

• Subject in an informal letter. Leave it out.
• “Yours faithfully” to a friend. Use a warm closing instead.
• Slang in a formal letter. Avoid “gonna”, “wanna” and emojis.
• Missing receiver’s address in a formal letter. Always include it.

Related Guides

For detailed rules, read our formal letter writing and informal letter format guides. Practise with write a letter to your friend and complaint letter class 10. Hindi students can read औपचारिक पत्र and अनौपचारिक पत्र.

Frequently Asked Questions

Remember the Key Points

Before you write, ask two questions: who will read it, and why? The answer tells you the difference between formal and informal letter style for that task. More formats are in our school letters section.