How long should a cover letter be, and what decides it

United Kingdom government guidance gives two answers that agree: one A4 page, three to five paragraphs. The useful question underneath is what fills them.

ConxfolioPublished 2026-09-12

— length is a symptom. Evidence is the cause.

Two public sources in the United Kingdom answer this question and they do not contradict each other. The nidirect government service says of a covering letter that "one A4 page is preferable" (nidirect.gov.uk). The National Careers Service calls it "a short letter, usually 3 to 5 paragraphs long" (nationalcareers.service.gov.uk). One page, three to five paragraphs. That is the whole external answer.

The reason people keep asking is that the number does not tell you what to do. A letter is not long or short by choice. It is long or short because of how much evidence went into it, and the fix for a bad length is almost never in the word count.

What the length is actually measuring

A letter that runs past a page is usually doing one of three things: repeating the résumé in sentences, describing personal qualities in adjectives, or explaining a gap at greater length than the gap deserves. None of those improve with editing at the sentence level, because the paragraph should not be there at all.

A letter that comes in very short is usually honest. It means the evidence available for this posting is thin. That is worth knowing before you send it, and it is a reason to look again at the évidence rather than to inflate the prose.

The measurement on this site

The check step of the cover letter builder reports the reading length of your draft and prints the range it is comparing against: 140 to 420 words, described in the product as a useful guide rather than a rule. Nothing blocks the export at any length. The review panel says so in its own words, that the notes below it are guidance rather than a gate.

On the draft in the picture above the letter came in at 79 words, which is below the range, and the panel said so without stopping anything. That draft had three proof paragraphs and no motivation paragraph, which is exactly the shape a short letter takes.

The arithmetic of a one-page letter

• Greeting and opening, around 40 words.
• Two to four proof paragraphs, 40 to 60 words each. This is the letter.
• Why this role, around 40 words, and only if you have something true to put there.
• Closing and signature, around 25 words.

That comes to roughly 250 to 350 words, which sits comfortably inside both the page and the range. Anything beyond it has to earn the space by carrying evidence.

Where the length goes wrong

The commonest failure is the letter that restates the résumé. A reader has both documents. A paragraph that says you worked at a company for four years has told them something they already read, in more words. The proof paragraphs are for the things the résumé could not carry: the result behind a line, the decision behind a result.

The second commonest is the letter that describes a temperament. Hard-working, detail-oriented, a strong communicator. These cost four words each and are discounted on sight, because every letter in the pile contains them and none of them can be checked. The same rule applies on the résumé, for the same reason.

How the builder keeps it honest

The engine selects sentences from your evidence rather than composing them, and where it cannot find evidence it returns fewer paragraphs instead of padding. That means the draft's length is a fair report on what you gave it. If the draft arrives short, the honest options are to add a proof paragraph you can support, or to send a short letter.

Paragraphs you write yourself are not constrained by that. You can add a proof paragraph at any point in the list and write it by hand; the letter beside the list changes as you type. What you cannot do is have the engine invent one for you, which is the point.

Two documents, two lengths

The letter is short because the résumé is doing the volume. Résumé length is a different question with different limits, and the two answers interact: a résumé that has already stated a result in a line does not need the letter to state it again. Between them, the letter should be the document you can read standing up.

If you are writing your first one and it comes in at 150 words, that is not a failure. A first letter is short by nature, and a short honest letter is read more often than a long careful one.

What length will not tell you

Nothing here predicts a reply. The reading-length note is a measurement of your draft and not a forecast about a person who has not read it yet. It is worth checking for the same reason you check a file opens: it is cheap, and the alternative is finding out afterwards.