One refers to the numeral “1” and means “a single unit”:
Won is the past tense of “win”:
When to Use One vs. Won
The word one refers to a single unit of something and is how the number “1” is written out (as in “one year old”) in print. One also can be used as a pronoun to refer to a generic single person or thing (as in “One never knows”).
The word won is the past tense of the verb “win,” which means to achieve victory (as in “won the game”).
Examples of One vs. Won
(In this sentence, “one” is the written form of the number “1.”)
(In this sentence, “one” is the pronoun referring to a single person.)
(In this sentence, “won” is the past tense of “win.”)
How to Remember the Difference
Like many homophones, these words are confusing because they sound alike but their meaning and spelling are different.
To decide which to use in a sentence, simply replace the “one/won” in question with another number, “two,” for example. If the sentence still makes relative sense with “two,” you should use the word “one.” If it no longer makes sense with “two” as a replacement, you should use “won.”
Theory Into Practice: Which Is Which?
Is the underlined word correct? See if you can tell.
Right: This example uses the pronoun for a single person, and “one” is correct.
Wrong: This example refers to a victory and should use “won.”
Right: This example shows an amount, and “one” is correct.
Wrong: This example shows the singular pronoun and should use “one.”
Right: This example refers to a victory, and using “won” is correct.