Do you need a cover letter, and when does it actually change anything

Sometimes the posting answers this and sometimes it does not. Where it does not, the question is whether your application has something the résumé cannot carry.

ConxfolioPublished 2026-09-12

— if there is a box for it, fill it.

The honest answer has three branches, and most advice collapses them into one. Whether you need a cover letter depends on what the posting asks for, on how much your application needs explaining, and on nothing else.

When it is required

When there is a field for it, or the posting names it. This is not a judgement call. An application that leaves a required field empty is an application that failed at the first checkbox, and no amount of quality in the résumé recovers it. Read the posting to the end: application instructions live in the last paragraph more often than anywhere else.

When it is optional and worth writing

• Your history needs one sentence of context. A move between industries, a break, a title that means something different at your employer than it does elsewhere.
• You are applying for something adjacent rather than identical. The letter is where you connect what you did to what they asked for, and the résumé cannot make that argument.
• You have a real reason for this employer. Not enthusiasm. A reason: something you know about their work that made you apply.
• The role is competitive and the pile is uniform. Two hundred similar résumés and forty letters is a pile where the letters are read.

When it changes very little

High-volume hiring where the posting asks only for a résumé and a start date. Agency applications where the résumé is forwarded on its own. Internal systems that discard attachments. In those cases a letter costs you nothing and gains you nothing, and the same ten minutes spent tailoring the résumé to the posting is better spent.

The trap is deciding you are in this case when you are not. Unless the posting tells you the letter is unread, the assumption that goes wrong least often is that somebody will open it. Where there is no posting at all, a speculative letter is a different exercise again.

What a letter can carry that a résumé cannot

A résumé is a record. It is in a fixed order, it is read in about ten seconds, and it has no room for a because. The letter is where the because goes: why this move, why this employer, why the thing on line four of your history is more relevant than it looks.

That is the whole case for writing one. If your application has no because in it, the letter has less to do, and a short one is the right answer.

How long it takes here

The cover letter builder asks for three things: the role, the company and the posting. If you already have a résumé in this browser it uses that as the evidence; if not, you can type your evidence one fact per line. The draft comes back with each proof paragraph carrying the line it came from, and every paragraph is editable. Ten minutes is a fair estimate for a letter you are willing to send.

What it will not do is write a reason for you. The motivation field is optional and its content is used exactly as you wrote it, which means an optional letter with nothing to say will come back honest and short. That is still a better answer than an empty field.

The one thing worth doing either way

Whether or not you write the letter, check that the document you are attaching can be read. The ATS résumé checker reads the file you already have, reports what a parser got out of it, and prints the arithmetic behind the score. It needs no job description and no account. A letter cannot rescue a résumé whose text layer arrives scrambled, and the format page covers what causes that.

What nobody can tell you

Whether the letter got you the interview. No tool here or anywhere else measures that, and any site that claims to is guessing. What a letter does is give a reader something to be interested in beyond a list of dates, which is a smaller claim and a true one.

If you decide to write one, the guide to writing it covers the four parts, and the length page covers what fills them.

The cost of writing one, honestly stated

Ten minutes, once the evidence is in one place, and less after the first. The reason it feels more expensive is that most people write each letter from nothing, which turns a selection problem into a composition problem. A single master list of results, kept current, is what collapses the two.

That is the same economy behind tailoring. The letter that takes an evening is the one whose evidence has to be remembered first; the letter that takes ten minutes is the one whose evidence was already written down. Getting the list right once pays for itself by the third application.