Any number to 21st and twenty-first, in figures and in words — including the three that break the pattern.
Type a number to see its ordinal, in figures and in words.
In figures
In words
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01 · what they are
An ordinal number says which one, where a cardinal says how many. Three books; the third book.
English writes ordinal numbers two ways and uses both constantly: in figures with a two-letter suffix — 1st, 2nd, 3rd — and in words — first, second, third. The figure form goes on dates, rankings, floors and addresses; the word form goes in prose, and in anything read aloud.
Neither form is difficult until you hit the numbers that misbehave, and English has a handful of those. Two rules cover all of them.
The distinction between the two kinds of number is worth keeping clear, because English blurs it in speech. "The third of May" and "three in May" use the same digit and mean unrelated things, and a form that asks for a date will accept either without complaining. Ordinal numbers are how English marks that a number is a label for a position rather than a count of anything, which is also why they never take a plural: there are three books, but there is only ever one third book.
02 · the suffix rule
The obvious rule — look at the last digit — is right most of the time and wrong in a way that shows. Eleven ends in 1 but is 11th. Twelve ends in 2 but is 12th. Thirteen ends in 3 but is 13th. The correct rule has two steps, in this order.
Step 1 — last two digits
11, 12 or 13 → th
11th, 12th, 13th. And in every hundred after: 111th, 212th, 1013th.
Step 2 — last digit
1 → st · 2 → nd · 3 → rd · rest → th
21st, 22nd, 23rd, 24th. Only reached if step 1 did not apply.
The order matters. Reversing the two steps produces 11st and 111st, which is the single most common bug in ordinal code and the reason this converter has a test that walks 11, 12 and 13 through five different hundreds.
There is a reason the exception exists and it is not arbitrary. Eleven, twelve and thirteen are not built from "one", "two" and "three" the way twenty-one and thirty-two are; they are older words that arrived whole, and their ordinals were formed before the pattern that governs the rest. The digits happen to end in 1, 2 and 3 only because of how we write them, not because of how the words are made.
03 · the spellings
Most ordinals are the cardinal plus "th": sixth, seventh, tenth. Six of them are not, and they are all common enough that the irregular form is the one you need.
| Number | Figure | In words |
|---|---|---|
| 1 | 1st | first |
| 2 | 2nd | second |
| 3 | 3rd | third |
| 4 | 4th | fourth |
| 5 | 5th | fifth |
| 8 | 8th | eighth |
| 9 | 9th | ninth |
| 11 | 11th | eleventh |
| 12 | 12th | twelfth |
| 13 | 13th | thirteenth |
| 20 | 20th | twentieth |
| 21 | 21st | twenty-first |
| 22 | 22nd | twenty-second |
| 40 | 40th | fortieth |
| 100 | 100th | one hundredth |
| 101 | 101st | one hundred first |
| 111 | 111th | one hundred eleventh |
| 1000 | 1000th | one thousandth |
04 · compounds
In a compound ordinal, everything except the final word stays cardinal. One hundred twenty-third, not "first hundred twenty-third". The hyphen between the tens and the units survives, and the ordinal lands on the very last piece: twenty-first.
The same holds when the scale word is itself the end of the number. Two thousand becomes two thousandth, three hundred becomes three hundredth. But 2,000,005 is "two million fifth", because the number does not end on the scale word.
This is why the converter builds the cardinal first and then changes one word, rather than trying to assemble the ordinal directly. It is the same rule, applied once, at the end.
05 · where they appear
Ordinal numbers turn up more often than people notice, and each setting has its own habits about whether to use the figure or the word.
▸ dates
American usage writes March 5, 2026 without a suffix and reads it aloud as "March fifth". British usage writes 5 March 2026 and reads it as "the fifth of March". Writing "March 5th" is common informally and avoided in most formal styles, because the suffix duplicates what the reader already supplies.
▸ monarchs and popes
The figure is Roman and the reading is an ordinal with a definite article: Elizabeth II is "Elizabeth the Second", Henry VIII is "Henry the Eighth". The article is never written, only spoken, which is why the written form looks like a cardinal and is not one.
▸ floors and addresses
The twenty-first floor, 42nd Street, the third door on the left. The figure form dominates in writing because it is shorter on a sign, and the word form takes over in speech.
▸ rankings and sequences
Finishing third, the second attempt, the ninth edition. Prose usually spells these out below tenth and switches to figures above, which is the same threshold most style guides apply to cardinal numbers.
The pattern across all four is the same: the figure form wins where space is short or the number is large, and the word form wins in running prose and in anything spoken aloud. Since a date or a monarch is read differently from how it is written, both forms are worth having at once, which is why the converter above returns them side by side rather than making you pick.
06 · mistakes
— 11st, 12nd, 13rd
+ 11th, 12th, 13th
The exception that catches every naive implementation. Eleven, twelve and thirteen take "th" no matter what their last digit is.
— fiveth, nineth, twelveth
+ fifth, ninth, twelfth
These three change shape rather than taking a plain "th". Nine drops its "e", twelve becomes twelfth, five becomes fifth.
— twentyth
+ twentieth
The tens end in "y" and swap it for "ieth": twentieth, thirtieth, fortieth, ninetieth.
— twenty-first-th
+ twenty-first
Only the last word of a compound becomes ordinal. Everything before it stays cardinal: one hundred twenty-third.
— 1ST, 2ND in body text
+ 1st, 2nd
The suffix is lowercase and not superscript in most house styles. Word processors raise it automatically; many style guides turn that off.
07 · questions
Q01
A number that gives position rather than quantity: first, second, third. The cardinal counts how many — three books — and the ordinal says which one — the third book. English writes them either in figures with a suffix (3rd) or in words (third).
Q02
Because the suffix comes from the last two digits, not the last one. Anything ending in 11, 12 or 13 takes "th": 11th, 12th, 13th, and equally 111th, 112th, 113th. Only outside that range does the final digit decide — 21st, 22nd, 23rd.
Q03
Check the last two digits first. If they are 11, 12 or 13, use th. Otherwise the last digit decides: 1 takes st, 2 takes nd, 3 takes rd, and everything else takes th. That two-step order is the whole rule.
Q04
Usually not. Most style guides set the suffix on the line — 1st, not 1ˢᵗ — and word processors that raise it automatically are generally switched off in publishing workflows. Either is legible; consistency within a document matters more.
Q05
In American usage the date is normally written without the suffix — March 5, 2026 — and read aloud as "March fifth". British usage often writes 5 March 2026, also read with the ordinal. Writing "March 5th, 2026" is common in informal text and avoided in most formal styles.
Q06
Only the final word takes the ordinal form: twenty-first, one hundred twenty-third, one thousand two hundred thirty-fourth. Everything before the last word stays cardinal, and the hyphen between tens and units is kept.
Q07
Zeroth exists and is used in computing and mathematics, where a sequence starts at zero — the zeroth element of an array, the zeroth law of thermodynamics. It has no place in ordinary counting, which starts at first.
Q08
Considerably. Both agree in gender and number with the noun, both shorten before a masculine noun — primer piso — and both are used far less than in English above tenth, where speakers switch back to cardinals. Each has its own page on this site.
Check for 11, 12 and 13 before looking at the last digit, and remember that fifth, ninth and twelfth are their own words. The converter above handles the rest.