Formal or Informal? Choosing the Right Register
How to recognise when to write formally or informally, with side-by-side examples of greetings, vocabulary, grammar and endings.
Register means the level of formality in your language. Using the wrong register is like wearing a suit to the beach or flip-flops to a job interview: the words may be correct, but they send the wrong message.
How to decide
Ask two questions about your reader:
- How well do I know them? A close friend, someone you've met, or a stranger?
- What's the relationship? Equal (classmate), or official (teacher, landlord, company, examiner)?
| Reader | Register |
|---|---|
| friend, family, classmate | informal |
| teacher you know, colleague, host family | neutral or semi-formal |
| company, council, unknown manager, exam essay | formal |
Side by side
| Informal | Formal | |
|---|---|---|
| Greeting | Hi Sam, / Hey! | Dear Mr Collins, / Dear Sir or Madam, |
| Reason for writing | Just wanted to tell you… | I am writing to inform you that… |
| Contractions | I'm, can't, it's | I am, cannot, it is |
| Verbs | find out, get, put off | discover, obtain, postpone |
| Asking | Can you send me…? | I would be grateful if you could send me… |
| Apologising | Sorry about… | I apologise for… |
| Ending | See you soon! / Take care, | I look forward to hearing from you. Yours sincerely, |
Vocabulary: phrasal verbs vs single verbs
Informal English uses many phrasal verbs. Formal English often prefers a single word of Latin origin.
- We need to cut down on costs. → We need to reduce costs.
- They looked into the problem. → They investigated the problem.
- The meeting was put off. → The meeting was postponed.
Phrasal verbs are not wrong in formal writing, but too many make a letter sound chatty.
Grammar that sounds formal
- Passive voice: Mistakes were made / It is recommended that…
- Impersonal phrases: It appears that…, There is evidence that…
- Longer noun phrases: the introduction of a new policy instead of when they introduced a new policy
Common mistakes
Dear Sir, I wanna complain about the hotel. It was really bad!!!
Dear Sir or Madam, I am writing to complain about my recent stay at your hotel.
Hi Ms Patel, Please find attached my homework. Yours faithfully, Ali
That last one mixes registers: a friendly greeting, a business phrase and a very formal closing. For a teacher you know, Dear Ms Patel, … Best wishes, Ali is natural.
Yours faithfully or yours sincerely?
In British English: Yours faithfully when you began with Dear Sir or Madam (you don't know the name), Yours sincerely when you used the person's name. In emails, Kind regards or Best regards works for both.
Quick practice
Fill in the gaps, then check.
- Informal: "Can you send me the info?" Formal: "Could you send me the ?"
- Informal: "Thanks a lot!" Formal: "Thank you very ."
- Informal: "I want to ask about..." Formal: "I am writing to about..."
- In a formal letter, write "I would" instead of the contraction "".
- Informal: "Talk soon!" Formal: "I look forward to from you."