The practical answer is 3-4% above to counteract the right-wing effect of the electoral college. Yes, it all matters on what states she wins.

The theoretical answer is that Kamala could get less votes, just like Trump did in 2016, and still “win.” It’s not practical because the swing states are more conservative than the median population of the country as a whole, which means it’s extremely unlikely those swing states will vote for Kamala while Trump gets more votes elsewhere.

The places you need to watch are Arizona, Michigan, Wisconsin, Georgia, Pennsylvania, and to a lesser extent Ohio, Minnesota and Florida. The 538 polls will give you a sense of where those states are leading, and you can see different maps here. polling is imperfect, and frankly I can’t take the anxiety of watching that data day-to-day.