Yup, pokerstove. I agree that weighted range calculations aren't so easy with pokerstove, but it's pretty easy to make a good estimate. Still, it's definitely useful, and a feature I expected to be in pokerstove the first time I used it.

Still, I don't get why you would focus on preflop calculations. Knowing whether to shove preflop is pretty easy, isn't it? The tough decisions are often when you face an overbet on the turn or river, in my experience.