Usually, a mixer grinder comes from 500 watts to 1400 watts. As you know that the higher the Watts is, the more energy it consumes.
If you are looking mixer grinder for wet/dry grinding and making chutney, a 500- a watts mixer grinder will be fine. If you like to cook south Indian food, then a 750-Watts mixer grinder will be fine. It has some advanced options or faster grinding performance than it can go to 1000+ watts mixer grinder.