How do you say how are an old in french?

You can't directly translate "how old are you" into French using "how are" and "old". Here's how you say it:

"Quel âge as-tu?" (formal, "You")

"Quel âge avez-vous?" (formal, "You" - plural or polite)

"Quel âge a-t-il/elle?" (formal, "He/She")

"Quel âge ont-ils/elles?" (formal, "They")

"Quel âge as-tu ?" (informal, "You")

"Quel âge a-t-il/elle ?" (informal, "He/She")

"Quel âge ont-ils/elles ?" (informal, "They")

Let me know if you have any other French phrases you'd like translated!