Quel is an interrogative French adjective that means which or what. Like most adjectives, it has four forms: masculine singular (quel) and plural (quels), and feminine singular (quelle) and plural (quelles). The following examples show all four forms in action:
Quel jour sommes-nous? (What day is it?)
Quelle heure est-il? (What time is it?)
Quels cours vas-tu prendre? (Which classes will you take?)
Quelles sont tes couleurs préférées? (What are your favorite colors?)
Both quel and qu’est-ce que are equivalent to what, so how do you choose? It isn’t difficult when you know what to look for. Quel is an adjective, and an adjective describes a noun, so that’s the big clue: Look for the noun that quel could accompany.
Here’s an example in English: In the question What dress will you wear tonight?, the noun associated with what is dress. And in What is the best restaurant around here?, what is tied to the noun restaurant. So for those two questions, you use quel in French, like so:
Quelle robe vas-tu porter ce soir? (What dress will you wear tonight?)
Quel est le meilleur restaurant par ici? (What is the best restaurant around here?)
Now contrast those sentences with a question like What did you do last night? No noun is associated with what in this question, so you use qu’est-ce que in French.
Qu’est-ce que tu as fait hier soir? (What did you do last night?)
French uses quel in two specific ways.
Quel plus a noun
Quel can be directly in front of the noun, followed by a yes/no question formulated with est-ce que or inversion. The following examples show you both versions:
Quelle robe est-ce que tu vas porter ce soir? (What dress will you wear tonight?)
Quelle robe vas-tu porter ce soir? (What dress will you wear tonight?)
In the format quel + noun + yes/no question, quel replaces the article that would normally precede the noun.
If the question includes a preposition like in at what time, use one of the following phrases:
preposition + quel + noun + yes/no question with est-ce que
preposition + quel + noun + yes/no question with inversion
For example, you can say À quelle heure commencerons-nous? (At what time will we start?)
Quel plus être plus a noun
The second way to use quel is by separating it from the noun. In this sentence construction, a conjugated form of the verb être (to be) always sits between quel and the noun like so:
Quels sont vos films préférés? (What are your favorite films?)
Quelle a été votre réaction? (What was your reaction?)
To get there, here’s how you proceed:
Find the noun the question is asking about and determine what its gender and number are in French.
For example, for What was your reaction?, réaction (reaction) is feminine singular.
Match the proper version of quel to the noun.
The feminine singular version of quel is quelle. Now you have quelle réaction.
Match the proper tense of être to the version of quel and the noun and insert it between the two words.
In this example, you need the past tense of être in the third person: a été. Insert it between quelle and réaction. Et voilà!