What is the rule for ordinal suffixes?

Numbers ending in 1 take st, in 2 take nd, in 3 take rd, and all others take th. The exception is 11, 12, and 13 (and any number ending in them), which always take th — eleventh, twelfth, thirteenth.

Why do 11, 12, and 13 use th instead of st, nd, rd?

They are pronounced as eleventh, twelfth, and thirteenth, so they end in th regardless of their last digit. This rule applies to any number ending in 11, 12, or 13, such as 111th or 512th.

How are larger numbers like 101 handled?

Only the last one or two digits matter. 101 ends in 1 but not 11, so it is 101st. 112 ends in 12 so it is 112th. The tool checks the last two digits for the 11–13 exception first.

Are negative numbers supported?

Yes. The suffix is chosen from the absolute value of the number, so negative four becomes -4th. Zero is written as 0th.

Number to Ordinal Converter

This tool converts a cardinal number (1, 2, 3) into its ordinal form (1st, 2nd, 3rd) by adding the correct English suffix. It is handy for dates, rankings, leaderboards, and any prose where positions are written out.

How it works

English ordinal suffixes follow a simple rule based on the final digits:

ends in 1 → st   (1st, 21st, 101st)
ends in 2 → nd   (2nd, 32nd)
ends in 3 → rd   (3rd, 43rd)
otherwise → th   (4th, 5th, 100th)

The one exception is the teens: any number whose last two digits are 11, 12, or 13 takes th (11th, 12th, 13th, 111th, 212th, 513th). The tool checks the last two digits for this exception first, then falls back to the last-digit rule.

Example and tips

21 becomes 21st, 112 becomes 112th, and 103 becomes 103rd. The exception always wins for the teens, which is why 13 is 13th even though it ends in 3. For negatives, the suffix is taken from the magnitude — -1 is -1st.