make a (big) difference (ALSO make all the difference)
to improve a situation (greatly):
Exercise can make a big difference to your state of health.
Putting up some new wallpaper has made all the difference to the place.

[TahlilGaran] Advanced Learner's Dictionary ▲

make a difference
to have an effect.
It is exciting to do something that really makes a difference in your community.

People don't realize that their vote can make a difference.

Usage notes: often used in the form make no difference:
It makes no difference to me if the game is televised or not.

[TahlilGaran] English Idioms Dictionary ▲

make a difference
cause a change in a situation
It doesn't make a difference whether he comes to the meeting or not.

[TahlilGaran] English Idioms Dictionary ▲

make a difference
v. phr. To change the nature of something or a situation; be important; matter.
John's good score on the test made the difference between his passing or failing the course.
It doesn't make a bit of difference if you are late to my party. I just want you to come.

[TahlilGaran] English Idioms Dictionary ▲