How to write dates, times and prices in a text

Write the date as words with the weekday in front (Thursday 19 November), the time with am or pm (10:30am, 5pm), the price with no empty pence (£25, not £25.00), and phone numbers in groups (07700 900 265). That's what the GOV.UK style guide and the NHS digital service manual both do, and between them they cover almost every number a business puts in a text. The point is speed. A text gets read in a couple of seconds on a lock screen, often by someone doing something else, and the formats that cause trouble are the ones that can be read two ways.

Each choice also has a cost in characters, and in a 160-character message that's a real trade-off. The longest way of writing an appointment time below uses more than twice the space of the shortest.

Why numeric dates get misread

The plainest statement of the problem is in RFC 3339, the Internet Engineering Task Force's standard for timestamps, published in July 2002. In a section on human readability, it says: "the date format '10/11/1996' is completely unsuitable for global interchange because it is interpreted differently in different countries." In the UK that's 10 November. To anyone who learned dates the American way it's 11 October. The RFC's answer for computers is to order dates from year to day (1996-11-10), and it also says "the use of 2-digit years is deprecated", which rules out 10/11/96.

For people, the answer is words. The GOV.UK A to Z style guide writes dates as "4 June 2017": no ordinal ("2 June and not 2nd June"), no comma between month and year, and a capital on the month. It allows truncated months such as "Jan" and "Feb" "when space is an issue", and a text is about as short of space as writing gets.

The NHS digital service manual disagrees on that last point, and its reason is worth knowing. It says: "As far as possible, spell out months in full. Screen readers read out shortened months (Jan, Feb and so on) in inconsistent and sometimes confusing ways." A text can be read aloud by a phone's screen reader too, so "Thu 19 Nov" can come out oddly where "Thursday 19 November" can't.

So which do you pick? The full "Thursday 19 November at 10:30am" costs 31 characters. "Thu 19 Nov at 10:30am" costs 21. "19/11 at 10:30" costs 14, but it's the format RFC 3339 warns about, and it drops the weekday. Ten characters is the price of the NHS version over the short one, and most reminders have ten spare. Write the long form, and shorten only when the count says you have to.

Put the weekday next to the date

The NHS manual's date format is "6 August 2018", with one addition: "If it's helpful to include the day of the week, for example for users booking appointments, we write dates like this: Wednesday 6 August 2018." People plan their week by days, not dates. "Thursday" tells someone whether it clashes with the school run; "19 November" makes them open a calendar.

The weekday also does a second job: it cross-checks the date. If a text says "Friday 19 November", the reader knows something's wrong (19 November 2026 is a Thursday) and can ask, where a bare "19/11" would sail through with a typo in it. That only works if the weekday is right, so anything that builds dates automatically should calculate the weekday from the date, never type it separately.

Words like "today" and "tomorrow" are the opposite case. They depend on when the text is read, which may not be when it was sent. GOV.UK's guide has a rule for news articles that applies just as well: "when referring to today (as in a news article) include the date". "Tomorrow, Thursday 19 November" costs more characters than "tomorrow" alone and can't be misread by someone who opens it after midnight.

Times: am, pm, midday and midnight

GOV.UK's times entry is short and specific: "5:30pm (not 1730hrs)", "midnight (not 00:00)", "midday (not 12 noon, noon or 12pm)", and "10am to 11am (not 10-11am)". The NHS manual agrees and adds two more: "5pm", not "5.00pm", and "5:30pm", not "5.30pm".

Midday and midnight get their own lines because 12am and 12pm are so easy to mix up. GOV.UK goes a step further with deadlines: "Midnight is the first minute of the day, not the last. You should consider using '11:59pm' to avoid confusion about a single, specific time." Its example is that "You must register by midnight on Tuesday 14 June" can be read as the end of Monday 13 or the end of Tuesday 14, while "by 11:59pm on Tuesday 14 June" can only be read one way. For a text, "Reply by 11:59pm on Sunday 22 November" is 38 characters and unarguable. (That's a Sunday, if you're checking.)

Leaving off am or pm is an easy slip to make. "Your table is booked for 8:00" is clear to the restaurant and a coin toss to anyone else, given that some restaurants open for breakfast. "8pm" is shorter than "8:00" and impossible to misread. Mornings are less risky, because few businesses take bookings at 10:30 at night, but "10:30am" is only two characters more and removes the doubt entirely. The 24-hour clock is unambiguous too, though both guides choose am and pm for public writing.

One more rule from GOV.UK matters if any of your customers might be abroad: add "UK time", as in "Monday to Friday, 8am to 5pm UK time". And if you schedule texts for the small hours, the clocks change on the last Sunday of October and March, which is covered in our post on scheduling texts around the clock change.

Opening hours and deadlines

Two more GOV.UK date rules are written for exactly the kind of text businesses send before a bank holiday. For deadlines: "when mentioning a deadline, use 'on or before'", as in "Submit the form on or before 6 September 2025". And for opening hours across several days, put "different days on a new line", for example "Monday to Friday, 9am to 5pm" and then "Saturday, 10am to 1pm" on the next.

Texts can carry line breaks (each one counts as a character), and the NHS manual's guidance on writing NHS messages recommends them: text messages "do not support formatting such as bullet points, numbered lists, bold text or headings", so "use line breaks to make text messages easier to read". A Christmas hours text for a hypothetical practice, one line per day, reads:

• Crown Dental Christmas hours:
• Thursday 24 December, 9am to 1pm
• Friday 25 to Monday 28 December, closed
• Tuesday 29 December, 9am to 5pm

That's 134 characters with the line breaks, one part. The compressed version people often send instead, "open 24/12 9-1, closed 25-28/12, open 29/12 9-5", is less than half the length and makes the reader decode four numeric dates and two unlabelled times. The same NHS page also says not to use "abbreviations or acronyms the patient may not be familiar with", which is a fair test for "hrs", "approx" and the rest.

Prices: pounds, pence and the euro sign

GOV.UK's money entry: "Use the £ symbol: £75", and "Do not use decimals unless pence are included: £75.50 but not £75.00". For small amounts it says to write pence out in full: "calls will cost 4 pence per minute from a landline". In a text, ".00" is three characters that say nothing, and dropping them makes the price quicker to read.

The symbols themselves cost different amounts. The pound sign is in the GSM 7-bit default alphabet that standard texts use, so it takes one of the 160 places. So does the dollar sign. The euro sign isn't in the main table; 3GPP TS 23.038 puts it in an extension table, reached with an escape character, so "€25" looks like three characters and uses four places. That rarely matters on its own, but a text priced in euros that counts to exactly 160 is two parts.

Ranges follow the same rule as dates and times: "£20 to £30", not "£20-£30". And if the text is promoting something, the price has to be the full price the customer will pay, which our post on prices in promotional texts covers in detail.

Phone numbers and other numbers

GOV.UK's telephone numbers entry says to "separate out the area, freephone, mobile or international code from the rest of the number", with examples including "020 7946 0457", "07700 900 265" and "+44 (0)29 2018 0542". A memorable number can be grouped to suit: "0800 80 70 60". In a text the spaces cost a character or two, and they're worth it. Eleven unbroken digits are hard to check against anything, and a reader who wants to call you back needs to be sure they've got the right number.

For other numbers, GOV.UK uses numerals for everything except "one" on its own, "a comma for clarity" above 999 (9,000), a % sign for percentages, and "500 to 900", not "500-900". The NHS manual adds that people "find numerals easier to read and they scan for them", and it uses numerals even for 1 and 2 in health content. Reference numbers are worth a thought too: the NHS manual lists "distinguishing the number 0 and letter O" among the things people who struggle with numbers find hard, so a booking code made only of digits, or with the confusable letters left out, is kinder than one that mixes them.

If your customers include people with limited English, the Home Office's content design guidance points out that many use online translators, and that translation tools leave acronyms untranslated. A numeric date comes through a translation exactly as ambiguous as it went in, where "19 November" comes out in the reader's own language.

A quick reference

Put together, a reminder written this way still fits comfortably in one part:

Crown Dental: your check-up is on Thursday 19 November at 10:30am. Reply YES to confirm or NO if you need a new time.

That's 117 characters, with the day, the date, the time and the action spelled out, and 43 to spare. The numeric version ("on 19/11 at 10:30") saves 17 characters and gives up both the weekday and the am.

CaptiFi Connect schedules campaigns for the time you choose, holds them back during quiet hours, and charges one credit per SMS part, so the only cost of writing the date in full is the characters, and our character counter shows whether you've got them. If the count says you haven't, cut words before you cut the weekday: "your check-up is on" can lose "check-up" long before "Thursday" needs to become "Thu".