Learn Spanish (Spain): ¿Cuántos años tiene el niño?

In Spanish, you don't say that someone "is" a certain age. Instead, you say they "have" a certain number of years. Because of this, you use the verb tener (to have). Literally, this sentence asks "How many years has the boy?".

Why is it cuántos and not just cuánto?

Cuánto means "how much" or "how many", and it has to match the noun it describes. Since años (years) is a masculine, plural word, cuánto must also be masculine and plural, becoming cuántos.

Why does the verb tiene come before the subject el niño?

In Spanish questions, it is very common to swap the order of the subject and the verb. Instead of keeping the standard statement order like "how many years the boy has", you put the verb first: cuántos años tiene el niño.

Does the squiggly line over the 'n' in años matter?

Yes, it is very important! The letter ñ is a completely different letter from n in Spanish, pronounced a bit like the "ny" in "canyon". If you forget the tilde (the wavy mark) in años, it changes into a completely different (and inappropriate!) word instead of meaning "years".