Business Letter Format, With Examples

The short answer

A standard business letter uses full block format: every line starts at the left margin, paragraphs are single-spaced with a blank line between them, and nothing is indented. The parts run in a fixed order: your address or letterhead, the date, the recipient’s inside address, a salutation ending in a colon, the body, a complimentary close such as “Sincerely,” space for your signature, and your typed name. University writing guides recommend 1-inch margins and an 11- or 12-point font, with Times New Roman the traditional choice.

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What is business letter format?

Business letter format is a set of layout conventions, not a law or a USPS rule. It tells the reader at a glance who wrote, when, to whom, and why, and it gives the letter a predictable shape that’s easy to file. A good business letter is brief, straightforward, and polite, and George Mason University’s Writing Center suggests keeping it to one single-spaced page when you can.

Writing guides agree on the core parts and their order but differ on small details, such as how many blank lines separate the parts. MIT’s Mayfield Handbook and Purdue OWL give the same advice: if your organization has its own letter style or template, follow it. Where university writing centers disagree, this article says so.

Full block, modified block, or semi-block: what’s the difference?

There are three common layouts. Purdue OWL calls full block the most common and semi-block the least used. Only the starting position of certain lines changes; the parts and their order stay the same.

Full block puts everything at the left margin; MIT’s Mayfield Handbook notes it usually carries a business letterhead at the top. Modified block moves the date, the complimentary close, and the signature lines so they start at the horizontal center of the page. Semi-block, which Gallaudet University’s English Center calls the indented-paragraphs form, is modified block with the first line of each body paragraph indented. A few guides vary: George Mason also centers the sender’s return address in modified block, and the University of Arkansas Walton College guide aligns those lines on the right.

How each part is aligned in the three business letter formats
Part	Full block	Modified block	Semi-block
Sender’s address (without letterhead)	Left margin	Left margin, or starting at the center (guides differ)	Left margin, or starting at the center (guides differ)
Date	Left margin	Starts at the center	Starts at the center
Inside address	Left margin	Left margin	Left margin
Attention, subject, and salutation lines	Left margin	Left margin	Left margin
Body paragraphs	Left margin, no indent	Left margin, no indent	First line indented
Close, signature, typed name, and title	Left margin	Starts at the center	Starts at the center
Initials, enclosure, and cc notations	Left margin	Left margin	Left margin

What are the parts of a business letter, in order?

From the top of the page to the bottom, a business letter can include up to 12 parts. Only the sender’s address or letterhead, date, inside address, salutation, body, close, and signature block appear in almost every letter; the rest are added when they’re needed.

Letterhead or sender’s address: your street address, city, state, and ZIP Code, without your name, which goes in the signature block.
Date: the date you finish the letter, with the month spelled out.
Inside address: the recipient’s name, title, company, and full mailing address.
Attention line (optional): routes a letter addressed to a company to a person or department.
Subject or reference line (optional): names the topic or a reference number.
Salutation: “Dear” and the recipient’s name, followed by a colon.
Body: single-spaced paragraphs with a blank line between them.
Complimentary close: “Sincerely,” or a similar phrase, followed by a comma.
Signature block: your handwritten signature, then your typed name and title.
Initials (optional): the writer’s and typist’s initials, used only when someone else typed the letter.
Enclosure notation (optional): tells the reader something else is in the envelope.
Copy notation (optional): “cc:” and the names of anyone receiving a copy.

How do you write the heading, date, and inside address?

If you use letterhead, it already carries the sender’s address, so start with the date; MIT’s Mayfield Handbook places it two lines below the letterhead. Without letterhead, type your street address, city, state, and ZIP Code at the top, which MIT starts 1–1½ inches from the top of the page. Purdue OWL, the University of Iowa, and Walton College all say to leave your name out of this block because it appears in the signature block, though Gallaudet’s samples do put it at the top.

Write the date in American order with the month spelled out, as in October 9, 2026. Purdue OWL notes that if you work on a letter over several days, the date line should show the day you finished it.

The inside address is the recipient’s mailing address. Purdue OWL says it’s always best to write to a specific person, with a courtesy or professional title such as Ms. or Dr.; MIT adds the person’s job title and company above the street address, city, state, and ZIP Code. Purdue says the inside address is left-justified in every format. Guides differ on spacing: Purdue leaves one blank line between the date and the inside address, while George Mason leaves two.

Where do the attention line, subject line, and salutation go?

Use an attention line when you’re writing to a company and don’t know the right person’s name, such as “Attention: Department of Accounting,” the example in Walton College’s guide. The same guide advises trying to find out the person’s name first.

A subject line states the topic (“Subject: Invoices”), and a reference line points to a number the reader will recognize (“RE: Invoice 1234”). You can use either or both. Walton College places the salutation two lines below the inside address or below the subject or reference line, so in that layout the subject line sits above the greeting. Gallaudet’s simplified format replaces the salutation entirely with a subject line in capital letters.

For the salutation, use “Dear,” the person’s title, and last name, then a colon: Dear Ms. Whitfield:. A colon is the business-letter convention; Purdue OWL says never to use a comma there, although it also describes “open punctuation,” which drops the marks after both the salutation and the close. If you don’t know the name, the University of Iowa suggests a job title, such as Dear Hiring Manager:, and calls “To Whom It May Concern” outdated. MIT suggests naming the department, as in Dear Technical Support:, and advises against Dear Sir or Madam.

How do you end a business letter?

After the last body paragraph, add a complimentary close such as “Sincerely,” “Sincerely yours,” “Respectfully,” or “Yours truly.” Capitalize only the first word and follow it with a comma. Then leave room to sign: George Mason, MIT, and Northern Michigan University’s Writing Center leave four lines between the close and your typed name, while the University of Iowa template leaves three. Sign in blue or black ink above your typed name, and if you’re writing for an organization, put your job title on the line below your name.

End notations go at the bottom of the last page, one per line. MIT’s handbook lists them in this order:

Initials: the writer’s initials in capitals and the typist’s in lowercase, as in MT/fjr or LCP:ecb. Purdue OWL says to omit them if you typed the letter yourself.
Enclosure: “Enclosure,” “Encl.,” or “Enc.,” optionally followed by the document’s name or the number of items, such as Enc. (2). MIT advises also mentioning each enclosure in the body.
Copies: “cc:” followed by each person receiving a copy, one name per line.

Northern Michigan University Writing Center: Parts of a Business Letter

What margins, font, and spacing should a business letter use?

No single rule governs business letter margins or fonts, but writing-center guidance is consistent enough to follow with confidence. Purdue OWL calls 12-point Times New Roman the generally accepted font and says Arial and similar fonts may be used. George Mason warns that a business letter is not the place to try out fancy fonts.

Before printing, check the letter in print preview. The University of Iowa suggests centering the letter on the page and making sure no sentence or single word is stranded at the top of a page.

Common business letter formatting conventions from university writing guides
Setting	Common convention	Source
Paper	US Letter, 8½ × 11 inches	Northern Michigan University
Margins	1 inch on all sides	University of Iowa
Font	Times New Roman or another readable font such as Arial	Purdue OWL
Font size	11 or 12 point	University of Iowa
Line spacing	Single-spaced, with a blank line between paragraphs	Purdue OWL, George Mason
Paragraph indents	None in full and modified block; first line indented in semi-block	Purdue OWL
Length	One page when possible	George Mason

Business letter example in full block format

Here is a complete fictional letter on company letterhead, line by line from the top of the page. Every line starts at the left margin. In the printed letter, a blank line separates each group, and four blank lines sit between “Sincerely,” and the typed name for the signature. The names, addresses, and phone number are placeholders.

Letterhead: Harbor Lane Print Co., 210 Market Street, Anytown, OH 12345, (555) 010-0142
Date: October 9, 2026
Inside address: Ms. Dana Whitfield / Office Manager / Brightwater Dental Group / 75 Main Street, Suite 210 / Anytown, OH 12345
Subject line: Subject: New delivery day for your monthly print order
Salutation: Dear Ms. Whitfield:
Body, paragraph 1: Starting with your January 2027 order, we will deliver your appointment cards and letterhead on the first Tuesday of each month instead of the first Friday. This letter confirms the change we discussed by phone on October 6.
Body, paragraph 2: The new schedule lets us print your order earlier in the week, so your staff will have stock on hand before weekend appointments. Your prices, quantities, and delivery address stay the same. The enclosed calendar lists each 2027 delivery date.
Body, paragraph 3: If Tuesday deliveries don’t suit your office, please call me at (555) 010-0142 by November 13, 2026, and we will keep your Friday schedule. Thank you for your business.
Complimentary close: Sincerely,
Signature block: [handwritten signature] / Marcus Lee / Operations Manager
Initials: ML/jr
Enclosure: Enclosure: 2027 delivery calendar
Copy: cc: Priya Shah, Accounts Receivable

How do you format a two-page business letter?

Print letterhead on the first page only; Walton College leaves the heading of later pages blank. MIT’s Mayfield Handbook says every page after the first needs a heading with the recipient’s name, the date, and the page number. For the example above, that heading would read Ms. Dana Whitfield, October 9, 2026, Page 2.

MIT also says to carry at least two lines of body text onto the last page and never to use a whole page for just the closing. If only the signature block spills over, tighten the wording until the close fits with the last paragraph.

More pages also mean more weight. A stamped First-Class Mail letter costs $0.82 for up to 1 ounce, $1.11 up to 2 ounces, and $1.40 up to 3 ounces at current USPS prices (unchanged since July 12, 2026).

How do you address the envelope for a business letter?

Copy the inside address onto the envelope, but in USPS order. Publication 28, USPS’s addressing standard, puts an attention line with the person’s name above the company name, and requires the company name, the street address, and the city, state, and ZIP+4 line to be the last three lines of the address block. It also notes that generally only five lines of address information are suitable for automated processing when the piece isn’t barcoded, so drop optional lines such as a department name if the block grows too long.

Put your return address in the upper left corner of the envelope front and keep both addresses on the same side, parallel to the long edge. USPS asks for no commas or periods. Publication 28 also says its abbreviations aren’t mandatory, so a spelled-out Street in the inside address is fine even though the envelope may read ST.

If you use a window envelope, fold the letter so the inside address shows through the window, as Northern Michigan University’s guide notes. For capital letters, line spacing, and more examples, see the envelope guide below.

How do you mail a business letter with proof of delivery?

For contract notices, disputes, or anything you may need to prove later, add Certified Mail. It gives you a mailing receipt and electronic verification that the letter was delivered or that delivery was attempted, and USPS keeps a delivery record that includes the recipient’s signature. It’s available with First-Class Mail and Priority Mail, travels as ordinary mail, and includes no insurance on a First-Class letter. To get evidence of delivery yourself, buy a Return Receipt when you mail the letter. For a postmarked mailing receipt, hand the letter to a Post Office employee, who dates the receipt.

IRIS can mail the finished letter for you. Upload it as a US Letter-size PDF, enter the sender and recipient addresses, and review the document, addresses, options, and total before you pay; IRIS prints it and mails it by USPS First-Class Mail to a US address. A one-page black-and-white letter is $3.20. Certified Mail adds $6.95 for letters up to six sheets ($10.15 for one black-and-white page), with tracking on your order page, and an electronic Return Receipt adds $2.91. IRIS can’t enclose physical items, so include any enclosures as pages in the same PDF. Order status isn’t proof of delivery, and IRIS doesn’t offer the hardcopy green-card Return Receipt.

Certified Mail costs for a 1-ounce business letter, current USPS prices (October 2026)
Option	Cost	What you get
Stamped First-Class Mail letter	$0.82	Delivery only, no receipt
Certified Mail at the Post Office	$5.55 fee + $0.82 postage = $6.37	Mailing receipt, online delivery status, and a USPS delivery record with the recipient’s signature
Electronic Return Receipt	+$2.91	Evidence of delivery (who received it and the date) by email
Hardcopy Return Receipt (green card)	+$4.65	The same evidence on a PS Form 3811 card mailed back to you
IRIS Certified letter, one black-and-white page	$10.15, including printing and postage	Tracking on your order page; electronic Return Receipt +$2.91

Sources & further reading

Product details checked against the IRIS API contract when this article was published. Platform references can change; consult the linked documentation when implementing.

Published by IRIS Postal Forms, operated by Great Lakes Computing Office LLC. Send a correction.

Put it into practice

Mail your business letter without stamps or envelopes

Upload the finished letter as a US Letter-size PDF and IRIS prints it and mails it by USPS First-Class Mail, from $3.20 for one black-and-white page. Need a delivery record? Add Certified Mail for $6.95, with tracking on your order page.

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