If you had a 4.0 on 117 hours and you got an F in a 3 hour course, your overall GPA would fall to 3.900 — that one F had an effect on the entire 4-years of college of only .100; a single bad grade, considered by itself, isn’t so damaging. It is really only 3/120th of your degree or 2.5% when considered by itself.

If we used the same example and you had a 3.0 GPA on 117 hours and a single 3 hour F; the effect on your GPA would only be -0.07 or a reduction to 2.93 — 0.07 isn’t all that significant in the bigger picture as long as you don’t have a bunch of them.

On your other question, some colleges allow grade replacement (retaking the same class replaces the old grade) some allow grade averaging (retaking the class doesn’t replace the grade, both attempts count in the GPA). The latter is the more common.

When transferring, most colleges won’t transfer an F grade at all and so it will appear to fall off of your transcript. Keep in mind though that most calculate academic honors and scholarships using the cumulative collegiate GPA (which will consider that F).

In the future, if you think you’re going to take an F (or D) then drop the class or ask about the possibility of an Incomplete.

My guess, if you had all straight A’s otherwise, an F wouldn’t do too much damage. But if you still want to correct it, you could try dilluting the damage by taking additional courses to increase the ration of good grades to bad.