Hi Kai, Both sentences can mean that you will call them shortly or that you will call them but only have a short time to talk. Great question and I hope this helps.

"I am going to call you" means you are committing to calling. "I will call you" is more a prediction than the commitment above. You plan on calling in the future ..... but there still remains a chance something will prevent you.

Well, yes and no - If someone told me - "I am going to call you real quick," or "I will call you real quick" - yes, I would think that they intended to call me very soon (meaning in the next minute or two, and certainly before five minutes were up). And native speakers of English would, and commonly do, use this wording. However, it's not grammatically correct English (native speakers say all sorts of things that are not strictly grammatically correct). "Real" and "quick" are adjectives, and should only be used to modify nouns. We can change them into adverbs by adding the ending '-ly,' creating "really" and "quickly." But doing that changes the meaning of the sentences slightly - "I am going to call you really quickly," or "I will call you really quickly" - - is ambiguous. I don't know whether the speaker means that they intend to call me very soon, or that they intend to call me for only a very short period of time, or possibly both. Because of this ambiguity, this wording isn't used very much. To tell me, in grammatically correct English, that you intend to call me very soon, you might say: - I am going to call you very soon. - I will call you right away. - I am going to call you immediately. - I will call you as soon as possible. - I am going to call you in a minute/in just a moment. To tell me, in grammatically correct English, that you intend to call me and speak only very briefly, you might say: - I am going to give you a quick call. - I am going to call you for just a minute/for just a moment.

Not exactly! It means more: I will call you (for a short phone call). As in, only a couple of minutes.

Thank you