Cardinal vs Ordinal Numbers: What's the Difference?
Last updated 19 June 2026
Cardinal numbers answer “how many” — one, two, three. Ordinal numbers answer “in what position” — first, second, third. Choosing the right form keeps dates, rankings, and lists clear.
Cardinal numbers
Cardinals count quantity: three apples, forty guests. They are the default form our converter produces.
Ordinal numbers
Ordinals mark order: first place, the 21st century. In words they usually end in -th, with the irregulars first, second, third, fifth, eighth, ninth, twelfth. Compound ordinals hyphenate like cardinals: twenty-first, forty-third.
Quick reference
| Number | Cardinal | Ordinal |
|---|---|---|
| 1 | one | first |
| 2 | two | second |
| 3 | three | third |
| 5 | five | fifth |
| 21 | twenty-one | twenty-first |
Every number page on this site lists both forms — for example, 21 in words.