Both parties are heading into Wisconsin tomorrow for a single contest of their respective parties.
There are 42 delegates up for grabs for the Republicans and 86 unpledged delegates up for grabs for the Democrats (ignoring the 10 superdelegates).
Right now, Hillary needs 43.50% of the remaining delegates in order to win the Democratic nomination and Bernie needs 56.55% of the remaining delegates. To this point, Hillary has performed well in the South and Bernie has performed well in the North and the West. There are no more southern states, but plenty of northern and western states have yet to hold their respective primaries and caucuses. Furthermore, in the last six contests, Bernie has won 65.93% of the delegates, well above the 58% threshold he needed to meet at the time.
On the Republican side, Trump needs 53.78% of the remaining delegates to secure the nomination and Cruz needs 82.29%. So far, Trump has won 21 out of 34 contests (61.76%). If he can win the winner-take-all state of Wisconsin tomorrow and the winner-take-most contest of New York two weeks later, then Trump will need a minority of the remaining delegates (probably 48%) in order to win whereas Cruz would need almost all of the remaining delegates (probably 93%). (As for Kasich, he currently needs 118.03% of the remaining delegates and, after New York, he will need about 138% of the remaining delegates. I think somebody’s holding out for a contested convention.)