The debate about cover letters has been going on for years. Some career advisors say always include one. Others say nobody reads them. The truth is somewhere in between, and it depends entirely on context.
When you absolutely need a cover letter
The application specifically asks for one. If the job posting says "please include a cover letter," not including one signals that you do not follow instructions. This alone can eliminate you.
Academic and research positions. Higher education and research roles almost always expect a cover letter. It is part of the standard application package alongside your CV, references, and research statement.
Government and nonprofit roles. These sectors tend to be more formal in their hiring processes. A cover letter is expected even if not explicitly requested.
Senior and executive positions. At the director level and above, a cover letter provides context that a resume cannot: your leadership philosophy, why you are interested in this specific organization, and what you envision for the role.
Career changes. When your resume does not obviously connect to the role, a cover letter bridges the gap. It explains why a financial analyst is applying for a product management role and how their skills transfer.
When you can skip it
The application does not ask for one and there is no upload field. If the system only accepts a resume file, they do not want a cover letter. Do not try to combine them into one document.
High-volume technical roles. Software engineering, data science, and design roles at tech companies typically do not require cover letters. Recruiters are screening for skills and experience, and they have hundreds of applications to process.
Staffing agency submissions. When a recruiter is submitting your resume to a client, they write the pitch. Your cover letter would not reach the hiring manager anyway.
You are applying through a referral. If someone inside the company referred you and the hiring manager knows you are coming, the cover letter adds little. Your referrer already made the case for you.
When it says "optional"
"Optional" means different things at different companies. Here is how to decide:
Include one if: the role is competitive, the company is small (your application gets more individual attention), you have something to explain (gap, career change, relocation), or you have a genuine connection to the company mission.
Skip it if: you are applying to a large company with a structured process, the role is technical and your resume clearly demonstrates your qualifications, or you are applying to many jobs and your time is better spent tailoring resumes.
A weak cover letter is worse than no cover letter. If you cannot write something specific and compelling for this particular role at this particular company, leave it out.
What a good cover letter actually does
A cover letter is not a summary of your resume. It is the answer to two questions: why this company, and why you?
The best cover letters are 3 to 4 paragraphs:
1. What role you are applying for and one sentence about why you are excited about this specific company (not generic flattery). 2. The most relevant thing from your background that makes you a strong fit. One specific achievement with numbers. 3. How your skills connect to what they need. Reference something from the job description. 4. A simple closing that invites next steps.
Total length: under 300 words. Recruiters will not read more than that.
The time math
Writing a good, tailored cover letter takes 20 to 30 minutes. If you are applying to 10 jobs per week, that is 3 to 5 extra hours.
If those jobs require a cover letter or you are in a competitive field where it makes a difference, that time is well spent. If you are sending them into a system that does not ask for them, you are better off spending that time tailoring your resume or networking.
The bottom line
Match the expectation. If they ask for one, write a great one. If they do not ask and you have nothing compelling to say beyond what is on your resume, skip it and invest that time in making your resume stronger for the specific role.