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The correct format for a business letter is block format: everything left-aligned, single-spaced, with a blank line between paragraphs and no indentation. It has six parts: your address, the date, the recipient's address, the salutation, the body, and the closing with your signature block.
| Format | How it looks | When to use it |
|---|---|---|
| Block (full block) | Every line starts at the left edge; paragraphs separated by blank lines, never indented | Default choice. What most companies, law offices, and government agencies expect. |
| Modified block | Body paragraphs are left-aligned, but the sender's address, date, and closing sit centered or at the right edge | Older, more traditional style. Fine, but looks slightly dated next to full block. |
| Semi-block | Like block, but each paragraph's first line is indented | Rare today. Reads like a book chapter; avoid it for business. |
Full block wins because it's the easiest to read and the hardest to get wrong. There's no judgment call about where the date should sit or how deep the indent goes. Type from the left edge, leave a blank line where you'd naturally pause, and you're done. If a template you're copying uses modified block, you can switch it to full block without offending anyone.
First, your address (the sender's), usually at the top left in block format. Skip this if it's already on your letterhead. Second, the date, written out in full: "October 5, 2026", never "10/5/26" or "05-10-2026", because number formats read differently across countries. Third, the recipient's inside address: their name and title, company, and full mailing address, the same block you'd put on the envelope.
Fourth, the salutation: "Dear Ms. Rivera:" with a colon, not a comma, in US business letters. (A comma belongs in personal letters and in British usage.) Fifth, the body: single-spaced, blank line between paragraphs, no indents. Sixth, the closing ("Sincerely,") with your handwritten or typed signature block beneath it.
A subject line sits between the salutation and the body, usually starting with "Re:" or "Subject:". It tells a busy recipient what the letter is about before they read a word, and it makes the letter easy to file and find later. For anything referencing an account, invoice, or case, always include one.
Typist initials (like "JQ/kl") used to show who dictated and who typed the letter. They're a relic of the secretarial era, and you can safely drop them. What you shouldn't drop: the enclosure notation if anything rides along in the envelope, and the "cc:" line if anyone else gets a copy. Both go below the signature block.
Three details separate a polished letter from a rough one. First, keep the letter to one page when you can. If it must run longer, a second page is fine, but don't shrink the type or squeeze the white space to force it onto one: a cramped letter looks worse than a two-pager. Second, never let the closing and signature land alone on a second page while the body ends on the first. That's called a dangling signature block, and it looks like an afterthought. Pull at least two lines of the body down with it.
Third, use a plain, readable font at 11 or 12 points: Times New Roman or Arial are the safe defaults. Resist the urge to get creative with typefaces; in business letters, an invisible font choice is a correct one. LetterAgent prints letters on standard 8.5x11in paper exactly as you provide them, so these same layout rules apply whether you print at home or have the letter printed and mailed for you.
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