Proper business letter format matters because a letter is often the first hard-copy impression you make on a client, regulator, or hiring committee. Unlike email, a printed letter signals that the matter is serious. Get the structure wrong and that signal misfires before the reader reaches your first sentence. This guide covers every section of a standard business letter, in the order it appears on the page.
The two standard formats
Most business letters follow one of two layouts: block format or modified block format. Block format is the more common choice in corporate settings. Every element, including the date, addresses, salutation, body, and closing, sits flush against the left margin. Nothing is indented.
Modified block format moves the date, closing, and signature to the center or right of the page. The body paragraphs stay left-aligned. Some writers also indent the first line of each body paragraph in this style. Pick one format and use it consistently throughout the letter. Mixing the two looks like an error.
Margins and font
Set all four margins to 1 inch. This is the standard for business correspondence in the United States and most English-speaking markets. If the letter is short, you can increase margins to 1.25 inches to fill the page without stretching the content thin.
Use a readable serif or sans-serif font at 11 or 12 points. Times New Roman 12pt and Arial 11pt are both widely accepted. Don't use decorative fonts. The letter should look clean, not creative.
Sender's address and date
If you're writing on company letterhead, the sender's address is already printed at the top. Skip it and start with the date. If you're not using letterhead, type your address first, flush left (block format) or centered/right (modified block), without your name above it. Your name goes in the signature block at the end.
The date sits two lines below the sender's address. Write it in full: August 12, 2026. Don't abbreviate the month or use a numeric-only format like 8/12/26. Numeric dates read differently in American and British conventions, which creates ambiguity in international correspondence. If your letter will travel across borders, the written-out month removes all doubt.
Recipient's address block
Leave two to four blank lines after the date, then type the inside address. This is the recipient's full mailing address as it would appear on the envelope.
- Line 1: recipient's name and title (e.g., Ms. Diane Torres, Senior Procurement Manager)
- Line 2: company name
- Line 3: street address
- Line 4: city, state, and ZIP (or city and postcode for international)
If you're unsure how to handle an unusual delivery situation, the guidance on using "care of" in an address covers how to route a letter through an intermediary correctly. For letters sent to multiple addresses or shared offices, that post will save you a formatting error.
Always try to address the letter to a named person. A letter addressed to a specific individual is more likely to be opened and acted on than one addressed to a department. If you genuinely don't know the recipient's name, see the section on salutations below.
The salutation
Leave one blank line after the inside address, then write the salutation. Use a colon after the name in business letters, not a comma. A comma is for personal correspondence.
Examples: Dear Ms. Torres: or Dear Mr. Okafor:
Use the recipient's last name unless you have an established first-name relationship. If you don't know the recipient's gender or they use a gender-neutral title, the guidance on Miss, Mrs, Ms, and Mx explains how to choose correctly without guessing.
If you genuinely can't identify a named recipient, Dear Hiring Manager: or Dear Customer Service Team: beats a generic opener. The phrase "To Whom It May Concern" is still grammatically acceptable but reads as impersonal in most modern contexts. Use a role-based salutation instead when you can.
The body of the letter
The body starts one blank line below the salutation. In block format, don't indent. In modified block with indented paragraphs, indent the first line five spaces or half an inch.
Structure the body in three parts:
Opening paragraph: State your purpose in the first two sentences. Don't bury the point. If you're requesting a meeting, say so. If you're responding to a complaint, acknowledge it directly. The reader should know exactly why the letter exists before the end of the first paragraph.
Middle paragraphs: Provide context, supporting detail, or the substance of your request. Keep paragraphs short. Three to five sentences per paragraph is a workable target. One idea per paragraph keeps the letter easy to scan.
Closing paragraph: State the action you want, or the next step you're committing to. Include a deadline if one applies. Be specific. "Please contact me by August 28, 2026" is clearer than "please reach out at your earliest convenience."
Single-space the body text. Add one blank line between paragraphs. Don't double-space between lines within a paragraph.
The complimentary close and signature
Leave one blank line after the last body paragraph, then write the complimentary close. Capitalize only the first word and follow it with a comma.
Common choices, from formal to warm: Yours sincerely, / Sincerely, / Regards, / Best regards,
The phrase "With best regards" sits toward the warmer end of professional closes and works well when you have an existing relationship with the reader. "Yours faithfully" is the traditional British close when you don't know the recipient's name.
Leave four blank lines after the close. This is your signature space. Type your full name below it, then your title on the next line, and your company on the line after that. Sign in the space between the close and your typed name.
Reference line and enclosures
A reference line (sometimes labeled Re: or Subject:) appears two lines below the inside address and two lines above the salutation. Use it when the letter concerns a specific account number, case file, or contract. Keep it brief: one line is enough.
If you're enclosing documents, type Enclosure: or Enc: one or two lines below the signature block, followed by a short description of what's included. If you're sending a copy to a third party, add cc: [Name] on the following line.
A quick formatting checklist
Before you print or send, confirm each of the following:
- Margins are 1 inch on all sides
- Font is 11pt or 12pt in a standard typeface
- Date is written in full (month spelled out)
- Inside address matches what will appear on the envelope
- Salutation ends with a colon
- Body paragraphs are single-spaced with one blank line between them
- Complimentary close has a comma, not a period
- Four blank lines appear between the close and your typed name
- Enclosures and copies are noted below the signature block
Common mistakes to avoid
The most frequent errors in business letter format aren't typos. They're structural: missing a blank line between sections, using a comma instead of a colon after the salutation, or signing without leaving enough space. Double-check the spacing every time. A letter that reads well but prints badly leaves the wrong impression.
Keep the letter to one page whenever possible. If the content genuinely requires two pages, add a header on page two with the recipient's name, the date, and the page number. Don't leave the second page looking like an orphan.
Finally, proofread on paper, not just on screen. Errors in formal business letters, particularly in names, titles, and addresses, can be costly. Print a draft before you print the final copy.