How Do You Spell 31st? | Correct Ordinal Spelling

What Does 31st Mean In English?

Before answering how do you spell 31st, it helps to understand what this little number actually represents. The form 31st is the ordinal form of the number thirty one, which matches the standard idea of an ordinal number in English. A cardinal number such as thirty one simply tells you how many items you have. An ordinal number such as 31st tells you the position of something in a list or sequence.

You will see 31st used for dates, for example 31st of March, and also for rankings, such as finishing 31st in a race. Whenever English switches from counting how much to describing position, the language usually moves from thirty one to thirty first, and the written short form changes from 31 to 31st.

Table Of Ordinals Up To 31st

Because 31st is part of a wider family of ordinal numbers, it helps to see how it sits in the full list from first to thirty first. This table shows the cardinal number, the numeric ordinal form with letters, and the full spelling in words.

Number	Ordinal Digits	Ordinal In Words
1	1st	first
2	2nd	second
3	3rd	third
4	4th	fourth
5	5th	fifth
6	6th	sixth
7	7th	seventh
8	8th	eighth
9	9th	ninth
10	10th	tenth
11	11th	eleventh
12	12th	twelfth
13	13th	thirteenth
14	14th	fourteenth
15	15th	fifteenth
16	16th	sixteenth
17	17th	seventeenth
18	18th	eighteenth
19	19th	nineteenth
20	20th	twentieth
21	21st	twenty-first
22	22nd	twenty-second
23	23rd	twenty-third
24	24th	twenty-fourth
25	25th	twenty-fifth
26	26th	twenty-sixth
27	27th	twenty-seventh
28	28th	twenty-eighth
29	29th	twenty-ninth
30	30th	thirtieth
31	31st	thirty-first

How Do You Spell 31st? In Words And Numbers

Now to the main point, how do you spell 31st in clear English. When you write it in digits with letters, the correct short form is 31st, using the digits three and one followed by the letters s and t. When you write the same idea in words, the standard spelling is thirty-first, with a hyphen linking the tens part thirty and the ordinal word first.

This pattern matches other ordinal spellings between twenty first and ninety ninth. You keep the hyphen between the tens word and the final part. So you write twenty-first, forty-second, or sixty-fifth. The same rule covers thirty-first. Modern dictionaries such as Merriam Webster record thirty-first with the hyphen as the regular written form.

Why Does 31st Take The Ending St?

Another point that can confuse learners is why 31st ends with the letters s and t instead of t h. The reason comes from the way English builds ordinal endings from the base words first, second, and third. For most numbers, the basic ordinal ending is t h, as you see in 4th or 10th. But the first three ordinals keep their own special letter endings.

The basic pattern for endings is simple. First maps to the ending s t, so any number that ends in the digit one usually takes s t. Second maps to n d, so numbers ending in two usually take n d. Third maps to r d, so numbers ending in three usually take r d. All other numbers take t h. That is why English uses endings like 21st, 32nd, and 43rd, but 24th or 56th.

Rule For Adding St To 31

If you are asking again how do you spell 31st in numeric form, you can rely on this simple rule. Look at the last digit of the number. Because 31 ends in one, you attach the s t ending that links back to first. The rest of the digits stay the same. So 31 becomes 31st, 41 becomes 41st, and 91 becomes 91st. This rule applies in dates, rankings, and any other use of ordinal numbers.

Spelling 31st In Full Sentences

Learning the correct spelling is one step. Next comes using thirty-first smoothly in real sentences. In writing, you will switch between the numeric form 31st and the word form thirty-first depending on style guides, formality, and space. Many school teachers ask students to write the word version when they practise spelling or write in a formal way.

You might also follow rules from a style guide such as the guidance from the Associated Press Stylebook or the recommendations in the Chicago Manual of Style. These resources often prefer word spellings like thirty-first when a number starts a sentence. In the middle of a sentence, they may accept 31st, especially in dates or technical descriptions.

Examples With Dates Using 31st

Dates are the context where learners see 31st most often. Here are a few sample sentences that show both ways to express the same date.

• School reopens on 31st August.
• School reopens on the thirty-first of August.
• The deadline is 31st March each year.
• The deadline falls on the thirty-first of March every year.

In these examples, both forms communicate the same idea. Writers choose between 31st and thirty-first based on style rules, space on the page, and how formal the text feels.

Common Mistakes With Spelling 31st

Because English spelling has plenty of patterns and exceptions, students often make small mistakes with ordinal forms. When working with how do you spell 31st, these are the slips that appear most often in homework, notes, or digital messages.

Writing Thirty First Without A Hyphen

The most common spelling error is dropping the hyphen and writing thirty first as two separate words. In fast messages, that choice does not block understanding, but in school work and formal writing the hyphen is expected. The hyphen shows that thirty and first join together as one idea, the ordinal form of the number thirty one.

Using Thirty Oneth Instead Of Thirty First

A second error comes from applying the usual t h ending to the full number. Learners sometimes write thirty oneth or thirty one-th when they try to mirror fourteenth or nineteenth. English does not follow that pattern here. The correct form keeps the irregular word first at the end, so thirty-first is the only standard spelling.

Mixing Up 31st And 32nd

Young learners may also copy ordinals too quickly and swap the ending. Writing 31nd or 31rd looks odd to experienced readers, but it is an easy slip for someone still learning. Reading the number out loud, thirty-first, helps fix the correct link between the last digit one and the s t ending.

Pronouncing Thirty First Clearly

Spelling and pronunciation support each other. When you say thirty-first out loud, you stress the first part thirty and then add a clear first. Some speakers drop the t sound in first in rapid speech, but when a learner practises, it helps to say both parts slowly and clearly. Over time, the spoken rhythm makes the spelling easier to recall.

Listening to recordings from standard dictionaries or language learning platforms can give a useful model. Many online dictionary entries for thirty-first include audio clips and simple example sentences. Hearing the word used in context reinforces the spelling pattern in a way that works well for students of English as a second language.

When Should You Write 31st Instead Of Thirty First?

Spelling rules matter, but writers also need to decide which form to pick on the page. The choice between the numeric form 31st and the written form thirty-first depends on purpose, audience, and the type of text you are working on. Some school exams may tell you exactly which form to use, while a casual message to a friend leaves the choice to you.

Guidelines For Everyday Writing

For everyday school writing or notes, a simple rule works well. Use 31st in dates, tables, or short labels where space matters. Use thirty-first in running text, essays, and where your teacher or examiner asks for words rather than digits. When you are not sure, many teachers prefer the written form because it checks spelling and number understanding at the same time.

For more formal publishing work, writers often follow reference sources that outline number rules. Guidance from major style guides usually supports using numerals plus endings, such as 31st, for dates and technical writing. The same guides often suggest spelling out ordinals at the start of a sentence.

Table Of Contexts For 31st

This summary table compares common situations where writers choose between 31st and thirty-first in English.

Context	Preferred Form	Example
Calendar dates	31st	She arrives on 31st October.
Formal letters	31st or thirty-first	Your rent is due on the thirty-first.
Start of a sentence	thirty-first	Thirty-first January marks the deadline.
Race results	31st	He finished 31st overall.
Spelling tests	thirty-first	Write the word thirty-first three times.
Math or statistics	31st	The value peaks on the 31st day.
Teaching materials	Both forms	Match 31st with thirty-first.

Tips For Remembering The Spelling Of Thirty First

Because how do you spell 31st is such a common classroom question, it helps to collect a few simple memory tricks. These small steps make it easier for learners to write the ordinal correctly every time.

Link First To The Letters St

Start by fixing a solid link between the word first and the letters s and t. Write first and circle the last two letters. Then write 1st, 21st, and 31st alongside it. This visual pattern shows that any numeral ending in one tends to carry the s t ending in its ordinal form.

Practise With Related Ordinals

Next, work with a short group of related numbers that share the same pattern. For example, practise writing twenty-first, twenty-first, and thirty-first across a page, switching between digits and words. Over a few days, this simple drill makes the spelling feel natural and automatic.

Use Date Sentences In A Notebook

Another friendly trick is to keep a small notebook where you write one sentence each day using an ordinal date. On days that show the thirty-first of a month, write both versions. You might write, Today is 31st May and Today is the thirty-first of May. Over time, these little practice lines fix both the numeric and written forms of the ordinal in your memory.

Why Correct Ordinal Spelling Matters

Accurate spelling of 31st and thirty-first shows that a learner understands both number value and order. It supports clear notes in maths, science, and history, where dates, lists, and ordered steps appear often in class work, homework, and revision sheets.

Good control of ordinals also helps in tests and real life. When how do you spell 31st feels automatic, students can focus on ideas rather than tiny spelling worries, and their writing looks careful in applications, reports, and everyday digital messages.

Over time, these small habits build confidence with ordinal numbers, not just the spelling of thirty-first.