Short answer
How to write a cover letter
A cover letter argues that you fit this specific role; the CV lists what you have done. One page, four paragraphs: why this role and this employer, evidence against their two or three main requirements, what you would bring, and a close.
If a sentence would fit any other application, it is doing nothing.
What it is for
The CV is a record. The cover letter is an argument, and the argument is that you fit this role at this employer for reasons you can evidence.
That difference decides everything about what goes in it. Repeating your CV in prose wastes the one document where you get to explain what the list means.
It also answers the questions a CV cannot: why you are applying, why here, why now, and how the pieces of an unusual background connect.
Where an employer says a cover letter is optional, write one. Optional means most applicants will not, which makes it a cheap advantage.
The four paragraphs
One page, three or four paragraphs, around 300 to 400 words. Longer is not read more carefully.
| Paragraph | Job | Rough length |
|---|---|---|
| Opening | The role, and why this employer specifically | 3-4 sentences |
| Evidence | Their two or three main requirements, each with a specific example | 6-8 sentences |
| Fit | What you would bring, and why the move makes sense for you | 3-4 sentences |
| Close | Availability, thanks, and a clear next step | 2 sentences |
The opening
Name the role and where you saw it, then say something specific about the employer. That second half is what makes the letter theirs rather than generic.
Specific means something you could not say about a competitor: a piece of work they did, a market position, a change they have announced, a person you spoke to and what they said.
'I am writing to apply for the Graduate Analyst role advertised on your careers site. Your submission to the consultation on regional funding was the clearest account of the measurement problem I have read, and it is the kind of work I want to be doing' is an opening.
What to avoid: 'I am writing to express my keen interest in', 'I believe I would be a perfect fit', anything about being a hardworking and motivated individual, and any sentence that begins by telling them what their own company does.
Evidence against their requirements
Read the job description and pick the two or three requirements that carry the most weight — usually the ones repeated, or listed first, or described as essential.
Then give a specific example for each. Not a claim that you have the skill; an account of a time you used it, compressed to two or three sentences with a result.
'The role asks for experience communicating quantitative findings to non-specialists. In my final-year project I presented a regression analysis of regional wage data to a panel including two local authority officers, and rewrote the summary twice after their feedback that the confidence intervals were doing more harm than good' is evidence.
Use their vocabulary. If they call it stakeholder management, use that phrase rather than a synonym — many applications are screened for terms before a person reads them.
Two or three requirements answered well beats eight answered thinly.
The fit paragraph
Short, and pointed at what you would bring rather than at what you would gain. Employers read the second as a reason to hire someone else.
Where your background is unusual, this is where you connect it. A physics graduate applying to policy work should explain the connection rather than leaving the reader to infer it.
One sentence on why this move makes sense for you is fine and grounds the application. 'I want to work on measurement problems in applied policy rather than in pure research, which is why a consultancy rather than a doctorate' is a reason.
The close
Two sentences. Availability if it is relevant, thanks, and something that reads as a next step rather than as a plea.
'I am available from July and would welcome the chance to discuss the role. Thank you for considering my application.'
Do not apologise for anything, do not say you look forward to hearing from them at their earliest convenience, and do not restate your enthusiasm a third time.
Formatting and practicalities
Address a named person where you can find one — the hiring manager, the recruiter, the person named in the advert. 'Dear Sir or Madam' is a last resort and 'To whom it may concern' reads worse.
Match the font and header to your CV so the two look like one application.
One page, always. If it runs over, the evidence paragraph is doing too much rather than the margins being too wide.
Send it as a PDF unless asked otherwise, named with your name and the role rather than 'cover letter final'.
Where the application form has a free-text box instead of an attachment, the same structure works without the letter formatting.
Speculative letters
A letter to an employer with no advertised vacancy is a different document and it works more often than people expect, particularly at smaller organisations.
It needs a reason for writing now: something they have announced, a piece of their work you engaged with, a person who suggested you get in touch.
Be specific about what you are asking for. 'I am looking for a graduate role in policy analysis and would value fifteen minutes to hear how your team is structured' is answerable; 'I would welcome any opportunities' is not.
Attach the CV and keep the letter shorter — three paragraphs. Follow up once after two weeks.
When you have gaps or a change of direction
Address them briefly and factually rather than hoping they are not noticed. A reader who spots an unexplained two-year gap will assume something worse than the truth.
One or two sentences: what happened, and what you did. 'I took eighteen months out to care for a family member, during which I completed two open-university modules in statistics.'
For a change of direction, the letter is where you explain the through-line. What the previous field taught you that transfers, and why the move is considered rather than a retreat.
Do not over-explain. The letter's job is to remove the question, not to justify your life.
Tailoring at volume
Write one strong letter, then rewrite the opening and the evidence paragraph for each application. Those two are the ones a reader uses to tell applications apart.
Keep a file of your evidence examples in two-or-three-sentence form so that each letter is selection rather than composition.
Check the employer's name in every draft before sending. Sending a letter with the wrong company in it is common, it is fatal, and it takes ten seconds to prevent.
The failures
Six, and the first two are why most letters do not help.
- Repeating the CV in prose.
- An opening that would fit any employer.
- Claims without examples — enthusiastic, hardworking, a team player.
- Explaining to the employer what their own organisation does.
- Over a page.
- The wrong company name, or the previous employer's, left in from the last version.
Frequently asked questions
How long should a cover letter be?
One page, around 300 to 400 words in three or four paragraphs. Longer is not read more attentively, and a letter that runs over usually has an evidence paragraph doing too much.
Should I write one if it is optional?
Yes. Optional means most applicants will not, which makes it a cheap advantage in a process where small differences accumulate.
What if I cannot find a name to address it to?
Look at the advert, the company site and LinkedIn for the hiring manager or recruiter. If there is genuinely no name, 'Dear Hiring Manager' is better than 'To whom it may concern'.
How do I open a cover letter?
Name the role, then say something specific about the employer that you could not say about a competitor — a piece of their work, a market position, an announcement. Not your keen interest.
Should I explain a gap in my CV?
Briefly and factually, in one or two sentences. An unexplained gap invites the reader to assume something worse than the truth, and the letter's job is to remove the question rather than to justify it.
Should the cover letter go in the email body or as an attachment?
Attach it as a PDF and put a two-line note in the email body pointing at it, unless the advert says otherwise. Pasting the whole letter into the email loses the formatting that makes it look like part of one application with your CV.
Do I need a cover letter for an online application form?
Where there is a free-text box asking why you are applying, that is the cover letter and the same four-paragraph structure works without the letter formatting. Where there is no box and no upload, there is nothing to send.
Can I reuse the same letter?
The evidence examples travel; the opening and the requirement-matching do not. Those are the two paragraphs a reader uses to tell applications apart, and they must be rewritten each time.