How to write a cover letter for MBB

The cover letter in consulting is that document many candidates underestimate — and that can cost them the interview. When they ask for it, it will be reviewed. That clear. It's not a formality that nobody reads. It represents between 20% and 30% of the weight in the decision to invite you to an interview, and while the consulting resume carries most of the weight, the cover letter is your opportunity to do something that the resume cannot: tell a story. In three paragraphs you have to answer the three questions every evaluator wants to know: why consulting, why this firm, and why you. If you do it well, you complement your resume in a way that no other document can. If you do it poorly — or worse, if you copy a generic template changing only the firm's name — you're sending a clear signal that you haven't taken the process seriously.

Structure of a consulting cover letter: the three paragraphs that matter

The consulting cover letter doesn't need to be long or elaborate. Three well-written paragraphs, just over half a page. That's the ideal length. When a cover letter extends to a full page or more, it loses impact. The recruiting team reviews hundreds of applications in each cycle and a cover letter that's too long works against you.

The first paragraph answers "why consulting?". Here it's not enough to say you're attracted to problem-solving or that you want to work in diverse teams — everyone says that. What works is connecting your motivation to a concrete experience that made you see that consulting was your path. Be brief and direct: what led you to want to be a consultant, and why now.

The second paragraph is the most important and the one most candidates get wrong: "why this firm?". It has to be completely specific to the firm and office you're applying to. It's not enough to change "McKinsey" to "BCG" and leave the rest the same. Each firm has a different culture, values, and projects, and your letter has to demonstrate that you've researched and that your interest is genuine. After reviewing hundreds of cover letters, the most repeated pattern is the generic paragraph that could apply to any company: "I'm attracted to your commitment to excellence and your approach to creating long-term value for clients." That says nothing. What works is mentioning something specific — a real project, a firm practice in a sector you're interested in, a conversation with someone from the office — and explaining why it resonates with you personally.

The third paragraph answers "why you?". This isn't about listing your achievements — that's what you have the resume for. It's about showing what you can contribute in your first months of work and, above all, your ability to learn and be receptive to feedback. MBB firms seek people who are coachable — who arrive eager to learn, not with the attitude that they already know everything. The tone should be a balance between confidence and humility.

Real mistakes in consulting cover letters (and how to avoid them)

The most serious error — and surprisingly frequent — is getting the firm's name wrong. Sending a cover letter to Bain that says "McKinsey" in the second paragraph. It seems impossible, but it happens in every interview cycle, both with analyst-level candidates and MBAs. A candidate who could have been strong is eliminated instantly. In each interview cycle there are several cases of this error, both in analyst-level candidates and MBAs. It's not rare — it's systematic. It's an attention to detail error that in consulting is unacceptable — if you can't review your own letter before sending it, how are you going to review analysis for a CEO?

The second most common error is tone. There are Spanish-speaking candidates who write in an overly formal way — "Dear Director of Recruiting" — and others who go to the other extreme, with a tone that's too casual. The correct point is professional without being stiff: as if talking to a senior colleague who you respect but feel comfortable with.

Another frequent error: talking about your skills as if they were perfectly developed competencies. Evaluators respond better when you frame your abilities as something you're developing and want to keep improving within the firm. There's an enormous difference between "I have excellent problem-solving skills" and "My experience leading data analysis projects in the energy sector has given me a solid foundation in problem-solving that I'm eager to apply and continue developing in consulting".

You also see frequently done name-dropping poorly. If you had a networking conversation with someone from the firm, you can mention it, but it has to be very subtle. Something like "after my conversation with [name] from the [office] team, where they told me about [specific topic], my interest in the firm deepened." But if it feels forced — if you're adding a name just to add it, without providing context — it doesn't add anything and can even detract.

How to personalize your cover letter for McKinsey, BCG, and Bain

If you're applying to multiple MBB firms at the same time — and most candidates do — you need different cover letters. Just changing the firm name isn't enough. The second paragraph, the "why this firm" one, has to be completely different for each. McKinsey, BCG, and Bain have different cultures, different approaches, and value different things in their candidates.

To really personalize, research. Go beyond the corporate website. Talk to current consultants or alumni. Read about projects the office you're applying to has completed in your sector of interest. Check out our guide to types of consulting firms to understand the real differences between MBB and be able to talk about them knowledgeably in your letter.

A real example, anonymized: a candidate from an MIM program in Spain applied to BCG Madrid. In their second paragraph, instead of talking generically about BCG's culture, they mentioned a specific conversation with a consultant from the office about projects in renewable energy in the Iberian Peninsula, connecting it to their previous experience in the energy sector. That specificity — specific office, specific sector, real contact — is what separates a cover letter that engages from one that's forgotten in two seconds. The difference between a letter that engages and one that's forgotten in two seconds isn't the candidate's profile — it's the level of research behind it.

In contrast, another candidate with an equally strong profile wrote a paragraph that could have been for any company in the world: "I'm attracted to the firm's reputation for its commitment to creating sustainable value for clients." This type of generic statement is the quickest way to make your letter not stand out.

Frequently asked questions about the consulting cover letter

How much weight does the cover letter really have versus the resume?

It represents between 20% and 30% of the weight in the decision to invite you to an interview. The resume carries most of the weight, but the cover letter can tip the scales when the profile is borderline. If it's well done, it complements and reinforces your candidacy. If it's generic or has errors, it can disqualify you even if your resume is competitive.

Do all MBB firms ask for a cover letter?

Not always, but when they ask it's mandatory and will be reviewed. Some offices request it as part of the standard process; others ask for it only in certain cycles or entry levels. The rule is simple: if the application platform has a field to attach it, send it. And if they don't explicitly ask for it but you can attach it, do it anyway — it never hurts.

Can I use the same cover letter for McKinsey, BCG, and Bain?

No. The second paragraph — the "why this firm" one — has to be completely different for each. If an evaluator perceives that your letter could apply to any company, your candidacy loses credibility. It's more work, yes, but it's the difference between a letter that engages and one that's discarded in seconds.

What's the ideal length of a consulting cover letter?

Three well-written paragraphs, just over half a page. If you extend it to a full page, it loses force. The recruiting team reviews hundreds of applications per cycle — conciseness is a signal that you know how to communicate efficiently, which is exactly what they're looking for.

Should I mention networking contacts in my cover letter?

You can, but naturally. If you had a real conversation with someone from the firm that strengthened your interest, mention it briefly: "After my conversation with [name] from the [office] team...". If it feels forced or artificial, don't add names just for the sake of adding them — it detracts more than it contributes.

Your cover letter is your first exercise in communication with the firm. Three paragraphs where you demonstrate that you've researched, that your motivation is real, and that you know how to be concise. If you want to go deeper into how to prepare your entire candidacy, check out our complete preparation guide. And to master the behavioral interview portion that comes with the case, Crack The FIT Interview prepares you with the methodology we've developed after over 300 interviews at MBB.