The ideal length
A cover letter should generally run 250 to 400 words, fitting comfortably on a single page with normal margins and font size. This is enough space for a strong opening, one or two paragraphs of evidence, and a closing, without stretching the reader's patience. Letters under 150 words often feel thin and generic. Letters over 500 words usually contain material that belongs on the resume or should be cut entirely.
Formatting basics that keep it professional
- Use a standard, readable font such as Calibri, Arial, or Georgia, at 11 or 12 point size.
- Keep margins between 0.75 and 1 inch on all sides.
- Use single line spacing within paragraphs, with a blank line between paragraphs rather than indentation.
- Match the visual style of your resume where possible, including font choice, so the two documents look like a set.
- Avoid unnecessary design elements like borders, icons, or colored text unless you are applying to a design or creative role where visual presentation is itself relevant.
File format and naming
Submit as a PDF unless the application specifically requests a Word document. PDF preserves formatting across devices and prevents accidental edits. Name the file clearly, for example FirstName LastName Cover Letter, rather than a generic name like document1 or a leftover filename from an old draft. If the application system has a text box instead of a file upload, format for that context: shorter paragraphs, no special characters that might not render, and no reliance on bold or italic formatting that could be stripped out.
A structure by paragraph count
A typical four-paragraph structure works for most applications: an opening hook, a paragraph on relevant experience with a specific result, a paragraph on why this company and role specifically, and a short closing. Some letters compress this into three paragraphs by combining the experience and company-fit sections, which can work well for more junior roles or when the letter is meant to be quick and punchy rather than building a longer case.
When it makes sense to break these rules
A senior executive letter making a detailed case for a leadership role might reasonably run slightly longer, closer to 450 words, if every sentence earns its place. A creative role might justify a more visually distinct format. These are exceptions, not defaults. If you are unsure, the standard one-page, 300-word, plain-formatted letter is the safer choice for the overwhelming majority of applications.
Formatting for different application systems
Some applicant tracking systems parse a submitted document into plain text automatically, which can break formatting like columns, text boxes, or unusual fonts. If a system offers a preview after upload, always check it before submitting, since formatting that looks fine in your original file can render strangely once processed. When in doubt, favor simple, linear formatting with no columns or text boxes, since this is the format most reliably preserved across different systems.
What to include in the header
A simple header at the top of the letter should include your name, phone number, email, and optionally your city and a link to your LinkedIn profile or portfolio if relevant. Avoid including a full street address, which is largely unnecessary for a modern application and adds clutter. Keep the header visually simple, matching your resume's header style, so the documents read as a coordinated set rather than being formatted independently of each other.
Spacing and alignment details that quietly matter
Left aligned text, rather than justified text, is generally easier to read on screen and avoids the awkward, uneven word spacing that justified alignment can create in a narrow document. Use consistent spacing between paragraphs throughout the letter, and avoid mixing single and double spacing within the same document, which can happen accidentally when pasting content from different drafts or sources.
If the letter might be printed
Although most cover letters are read on screen today, some hiring processes, particularly for government roles or more traditional organizations, still involve printing applications for a review committee. If this is a possibility, avoid very light font colors or small font sizes below 11 point, both of which can become harder to read once printed, and stick to standard letter or A4 page sizing depending on the region you are applying in.
Keeping format consistent across your whole application set
If you are applying to many roles over a period of weeks, it is easy for formatting to drift slightly between versions, a slightly different font size here, a margin adjustment there. Periodically compare your most recent letter against your original template to make sure small inconsistencies have not crept in, since a hiring manager who happens to compare notes with a colleague on a shared candidate, or who simply opens your resume and letter side by side, will notice if they look like they came from two different documents entirely.
Keeping one clean master template
A practical habit is to maintain a single, carefully formatted master version of your cover letter template, and always duplicate from that master file for each new application rather than editing a previous application's file directly. This prevents small formatting drift from accumulating over time and makes sure every version starts from the same clean baseline.
A short summary to keep on hand
One page, 250 to 400 words, an 11 or 12 point standard font, normal margins, PDF format, and a header that matches your resume. These few defaults cover the overwhelming majority of applications and free up your attention for the actual content of the letter, which is where the real decision gets made.
Keep this short list somewhere easy to reference so you are not relitigating basic formatting choices for every new application. The time saved adds up quickly over the course of a full job search.