Learn Spanish (Spain): ¿Cuál es tu edad?

When asking for a specific piece of personal information (like a name, phone number, or age) using the verb es (is), Spanish uses cuál instead of qué. If you asked ¿Qué es tu edad?, it would sound like you are asking for the dictionary definition of the word "age"!

Why isn't there an accent mark on tu?

The word tu without an accent means "your". The word tú with an accent means "you". Since we are saying "your age", we use the one without the accent mark.

Is it better to say ¿Cuántos años tienes? or ¿Cuál es tu edad?

¿Cuántos años tienes? (literally "How many years do you have?") is the most common and natural way to ask someone's age in everyday conversation. ¿Cuál es tu edad? is perfectly correct but sounds a bit more formal, like a question you might hear at a clinic or read on an official form.

Is edad a masculine or feminine word?

It is feminine (la edad). As a helpful rule for beginners, almost all Spanish words that end in -dad (like la ciudad or la universidad) are feminine words.