How do you say "long" in reference to time in Japanese. Ex: how would you say this movie is long

Question

Answer

I'd say この映画は長いです

When we use the word 長い refering to a film, we understand we are refering to the time it takes. 
I hope this helps!!

Answer

In Japanese, the same word is used for time as is used for length or distance. That word is 長い (ながい), so you might say:

この映画は長いです。(this movie is long)

OR

この映画は時間がたくさん掛かりました (this movie took a lot of time)

The first one is more likely, however.