Ordinal numbers
A cardinal number counts how many. An ordinal says which one in a sequence. This turns one into the other, in words and in the short form.
English
A whole number, in figures or words: 21, 21st or twenty-one. Ordinals do not apply to decimals.
Ordinal in words
Short form
Cardinal:
The seven irregular ordinals
Most ordinals are the cardinal with “th” on the end. These seven are not, and they are the ones people get wrong. More on the two kinds of number word.
| Cardinal | Ordinal |
|---|---|
| one | first |
| two | second |
| three | third |
| five | fifth |
| eight | eighth |
| nine | ninth |
| twelve | twelfth |
The teens rule
The short form ends in “st”, “nd” or “rd” after a 1, 2 or 3, except in the teens, where everything takes “th”. So 21st and 121st, but 11th, 12th, 13th and 111th. This is the rule that most often trips up a short form written by hand.
One to twenty
- 1st first
- 2nd second
- 3rd third
- 4th fourth
- 5th fifth
- 6th sixth
- 7th seventh
- 8th eighth
- 9th ninth
- 10th tenth
- 11th eleventh
- 12th twelfth
- 13th thirteenth
- 14th fourteenth
- 15th fifteenth
- 16th sixteenth
- 17th seventeenth
- 18th eighteenth
- 19th nineteenth
- 20th twentieth
The tens
From twenty to ninety, the y becomes ie before the th.
- 20th twentieth
- 30th thirtieth
- 40th fortieth
- 50th fiftieth
- 60th sixtieth
- 70th seventieth
- 80th eightieth
- 90th ninetieth
- 100th one hundredth
Cardinals for comparison
- 1 one
- 2 two
- 3 three
- 4 four
- 5 five
- 6 six
- 7 seven
- 8 eight
- 9 nine
- 10 ten
- 11 eleven
- 12 twelve