Intermediate · B1–B2

Formal vs Informal English

The way you write and speak changes depending on your audience and purpose. Formal English is used in professional and academic contexts; informal English is for everyday conversation and casual writing.

When to use formal or informal English

Formal EnglishInformal English
Academic essays and reportsText messages and chats
Business emails and lettersEmails to friends
Job applicationsSocial media posts
Presentations and speechesEveryday conversation
Legal and official documentsPersonal diaries and journals

Key differences: vocabulary

InformalFormal
getobtain, receive, acquire
showdemonstrate, illustrate, indicate
askenquire, request, seek
useutilise, employ, apply
big / hugesignificant, substantial, considerable
helpassist, support, facilitate
needrequire, necessitate
thinkconsider, believe, conclude
startcommence, initiate, begin
endconclude, terminate, finalise

Key differences: grammar and style

FeatureInformalFormal
ContractionsI'm, don't, it's, they'veI am, do not, it is, they have
Phrasal verbsfind out, give up, put offdiscover, abandon, postpone
Sentence lengthShort, punchy sentencesLonger, more complex sentences
Passive voiceRare (active preferred)More common
Personal pronounsI, you, we freely usedOften avoided; impersonal style
Slang / colloquialismsCommon: cool, loads, gonnaAvoided entirely
Hedging languageLess commonIt could be argued that…, It appears that…
Same message — two registers

Informal: "Can you send me the report ASAP? I need it for a meeting."

Formal: "I would be grateful if you could send me the report at your earliest convenience. I require it for an upcoming meeting."

Informal: "The new law has loads of problems."

Formal: "The new legislation presents a number of significant challenges."

Email openings and closings

InformalFormal
OpeningHi Tom, Hey! Dear Maria,Dear Mr Collins, Dear Sir/Madam,
ClosingThanks, Cheers, See you, Take care,Yours sincerely, Yours faithfully, Kind regards,

Register tip: Before you write, ask yourself: Who is my audience? What is my purpose? A text to a friend and a cover letter to an employer require completely different registers. Getting the register wrong is as noticeable as a spelling mistake.