A cover letter is not a summary of your resume in paragraph form. It is a short, focused argument for why you and this specific role are a fit, written in your own voice. Done well, it adds context a bulleted resume cannot, connects your experience to the employer's needs, and shows genuine interest. Done poorly, it repeats your resume and gets skipped.
This guide gives you a reliable structure, shows how to open and close with impact, and lists the mistakes that quietly sink otherwise strong candidates.
Key takeaways
- A cover letter complements your resume, it does not repeat it, it adds context and motivation.
- Keep it to about 250 to 400 words in three to four tight paragraphs on a single page.
- Open with a specific hook, not "I am writing to apply for..." Address a real problem or a genuine reason you want this role.
- Show you researched the company by connecting your experience to its actual needs.
- Always tailor it, a generic letter is worse than no letter.
Do you even need a cover letter?
If an application provides a field for one, or the posting requests it, write one. When it is optional, a strong letter is still an advantage for roles you genuinely want, especially in competitive fields, career changes, or when you have a specific story that explains your fit. If the field is truly optional and you can only produce a generic template, your energy is better spent tailoring your resume.
The structure that works
Opening paragraph: the hook
Skip the robotic opener. State the role, then immediately give a specific reason you are a strong fit or a genuine reason you are drawn to this company. One or two sentences that make the reader want to continue. If you were referred by someone, name them here.
Body paragraph(s): the proof
This is the core. Pick one or two of your most relevant achievements and connect them directly to what the job needs. Do not list everything, choose the evidence that maps to the top requirements in the posting, and briefly explain the impact. This is where you show you understand the role and have done the work before.
Closing paragraph: the call to action
Reaffirm your interest, express enthusiasm for a conversation, and thank the reader. Keep it confident and brief. Avoid needy or presumptuous phrasing; a simple statement that you would welcome the chance to discuss how you can contribute is enough.
How to research fast
Personalization is what separates a real cover letter from a template. Spend ten minutes on the company: read the About page, a recent announcement, and the job description itself. Find one authentic point of connection, a product you admire, a challenge the role clearly exists to solve, a value that matches your own, and reference it specifically. Generic praise (I love your innovative culture) reads as filler; a specific observation reads as genuine interest.
Formatting and length
- One page, about 250 to 400 words, three to four short paragraphs.
- Address a specific person when you can find the name; otherwise a simple "Dear Hiring Team" is fine.
- Match the font and header style of your resume so they look like a set.
- Save as a PDF unless the posting requests otherwise.
- Proofread twice, especially the company name and the role title.
Mistakes that get letters ignored
- Restating your resume line by line instead of adding context.
- A generic letter with the company name swapped in, reviewers can tell instantly.
- Making it about what you want rather than what you offer the employer.
- Being too long, past one page, most letters go unread.
- Typos, or worse, the wrong company name left in from a previous application.
Frequently asked questions
How long should a cover letter be?
About 250 to 400 words on a single page, in three to four short paragraphs. Long enough to make a specific argument, short enough to be read in under a minute.
Do I need a cover letter if it is optional?
For roles you genuinely want, a tailored letter is an advantage, especially for competitive roles or career changes. If you can only produce a generic template, focus that time on tailoring your resume instead.
How do I start a cover letter?
Skip "I am writing to apply for." Open with a specific hook: a concrete reason you are a strong fit or a genuine, specific reason you want to work at this company. Name a referral if you have one.
Should I repeat my resume in my cover letter?
No. The letter should add context and motivation the resume cannot, connecting one or two of your most relevant achievements to the specific needs of the role.