You're sitting there, staring at a blank Google Doc or a crisp sheet of stationery, and suddenly you freeze. It's the simplest thing in the world, right? But the moment you actually have to figure out how to write a date in a letter, your brain starts playing tricks on you. Do you use a comma after the year? Is "2nd" better than just "2"? Should you stick to the American style or go International? Honestly, it depends entirely on who is opening that envelope.
Getting it wrong isn't going to end the world, but it can make a formal business inquiry look like a casual note passed in middle school. Or worse, if you're writing to someone in London and you use the US format, they might think your deadline is months away from when you actually intended it to be.
Dates are basically the timestamp of your credibility.
The Standard American Way (And Why It Sticks)
In the United States, we’ve collectively agreed on a specific rhythm: Month, Day, Year. It feels natural to us. You write October 12, 2025. There is a very specific reason for that comma after the day—it separates the two sets of numbers so they don't bleed into each other. Imagine writing October 12 2025. It looks cluttered. It's messy.
Most style guides, including the Gregg Reference Manual—which is basically the holy grail for administrative professionals—insist on this format for professional correspondence. You’ll notice there is no "th" or "st" attached to the number. We call those ordinals. While you might say "October twelfth," writing it as "October 12th" in the date line of a formal letter is generally considered a bit amateurish. Stick to the plain cardinal number.
Where people really trip up is when the date is sitting in the middle of a sentence. If you write, "On October 12, 2025, the contract will expire," you actually need a second comma after the year. Most people forget that one. It’s a small detail, but it’s the kind of thing an eagle-eyed HR manager or a legal clerk will notice instantly.
Going International: The Day-Month-Year Logic
Outside of the US, the rest of the world looks at our Month-Day-Year format and thinks we're a little bit crazy. They prefer the logical progression from the smallest unit to the largest: Day, then Month, then Year.
If you are writing to a business partner in the UK, Australia, or pretty much anywhere in Europe, you should probably use 12 October 2025.
Notice something different there? No commas.
Since the month (a word) is separating the two numbers (day and year), you don't need a comma to keep them apart. It's clean. It's efficient. It's also the standard for the United Nations and the U.S. Military. If you've ever seen a military memo, you know they don't mess around with unnecessary punctuation. They use 12 OCT 2025 or 12 October 2025.
The ISO 8601 Exception
Then you have the techies and the international scientists who use ISO 8601. This is the 2025-10-12 format. It’s designed to prevent any possible confusion between a Californian and a Parisian. While it's brilliant for filing digital documents or naming files on your computer so they sort chronologically, it's rarely used in the actual "heading" of a formal letter. It feels a bit cold. A bit robotic. Unless you’re writing a highly technical report or a data-heavy memo, maybe skip this one for your standard cover letter.
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Where Does the Date Actually Go?
Placement matters just as much as the format. In a standard block-style business letter—which is the most common format used today—everything is left-justified. You don't indent. You don't center. You just start at the top left.
Typically, you want to place the date about two inches from the top of the page. Or, if you're using letterhead, place it two spaces below the last line of the letterhead address.
If you’re feeling a bit more old-school and using modified block style, you might move the date (and your closing signature) to the center point of the page or justified to the right. This is a bit more traditional and carries a certain "executive" weight to it, but it’s becoming less common in the digital age.
Addressing the "Ordinal" Temptation
I get it. You want to write January 1st or March 3rd. It sounds more like how we talk. In a casual "thank you" note to your aunt or a quick handwritten invite to a backyard BBQ, go for it. It adds a touch of personality.
But in the world of Business Writing, those little letters (st, nd, rd, th) are just clutter. Professionalism usually demands the leanest version of the truth. According to the Associated Press (AP) Stylebook, which journalists live by, you should always use figures without ordinals. Even if you're writing a news release that's meant to look like a letter, stay away from the "th."
Common Blunders to Avoid
- Abbreviating months: Never write Jan. 15, 2026 in the date line of a letter. It looks lazy. Write the whole thing out. Space is rarely that limited on a piece of paper.
- All-numeric dates: Writing 10/12/25 is a recipe for disaster. In the US, that's October 12th. In the UK, that's December 10th. If you're sending a letter, use the month's name to eliminate any "wait, when is this happening?" moments.
- Leading zeros: Don't write October 05, 2025. This isn't a computer program. Just write October 5.
The Cultural Nuance of Formal Invitations
If you are writing a letter that doubles as a formal invitation—say, for a high-end corporate gala or a wedding—the rules change entirely. In these cases, you actually spell out everything.
The twelfth of October, Two thousand twenty-five.
It’s posh. It’s slow. It signals to the reader that this event is a big deal. You wouldn't use this for a resignation letter or a follow-up on an invoice, but for the "big" moments, spelling out the date is the ultimate mark of formality.
Practical Steps for Your Next Letter
Before you hit print, run through this mental checklist to make sure your date looks exactly how it should.
First, identify your audience. If they are in the US, use Month-Day-Year. If they are international or military, go with Day-Month-Year.
Second, check your punctuation. If you used the American style, make sure that comma is there after the day. If you used the International style, make sure the commas are gone.
Third, look at the font. The date should be in the same font and size as the rest of your letter. Changing the date to italics or bold makes it look like a template error.
Finally, ensure the spacing is correct. You want at least one blank line (sometimes two or four depending on the layout) between the date and the recipient's inside address. This "white space" makes the letter readable and professional.
By following these conventions, you aren't just "writing a date." You're signaling to your recipient that you understand professional norms and respect the details. It’s the difference between a letter that gets read and a letter that gets filed in the "unprofessional" pile. Stick to the full name of the month, leave out the "st/th" ordinals, and keep your placement consistent.