Ordinal Number Converter
Convert numbers to ordinals — 1 becomes 1st, 22 becomes 22nd — and spell them out (twenty-second), with the suffix rules explained.
Mode
Ordinal suffix rules
| Rule | Suffix | Examples |
|---|---|---|
| Last digit is 1 (not 11) | st | 1st, 21st, 101st |
| Last digit is 2 (not 12) | nd | 2nd, 22nd, 142nd |
| Last digit is 3 (not 13) | rd | 3rd, 33rd, 103rd |
| Ends in 11, 12, or 13 | th | 11th, 12th, 113th |
| Everything else | th | 4th, 9th, 20th, 100th |
The teens exception is the one everyone trips over: 11, 12, and 13 always take "th" because they are pronounced eleventh, twelfth, thirteenth — so 111th and 112th are correct, while 21st and 22nd follow the last-digit rule.
Frequently Asked Questions
- What is an ordinal number?
- An ordinal number expresses position or rank in a sequence — 1st, 2nd, 3rd, 4th — as opposed to cardinal numbers (1, 2, 3, 4), which express quantity. In words, the ordinals are first, second, third, fourth, and so on.
- Why is 11 written 11th and not 11st?
- Numbers ending in 11, 12, or 13 always take "th" — 11th, 12th, 13th, 111th, 212th — because they are pronounced eleventh, twelfth, thirteenth. The st/nd/rd suffixes only apply when the last digit is 1, 2, or 3 outside those teen endings, so 21st and 22nd are correct but 11st and 12nd are not.
- How do I spell out ordinal numbers?
- Convert the number to words, then make only the last word ordinal: 22 is twenty-second, 45 is forty-fifth, 130 is one hundred thirtieth. Note the irregular forms: first, second, third, fifth, eighth, ninth, twelfth, and tens ending in -y change to -ieth (twenty → twentieth).
- Should I use ordinals in dates in academic writing?
- No. APA, MLA, and Chicago all write dates with cardinal numerals — "July 28" or "28 July 2026", never "July 28th". Ordinals belong in rankings, editions ("2nd ed."), centuries ("the 19th century"), and sequence descriptions.
- Can I convert a whole list of numbers at once?
- Yes. Switch to batch mode and enter one number per line — every line is converted to both its suffix form (22nd) and its spelled-out form (twenty-second), ready to copy.