Here are some ways the Republican and Democratic nominating contests could unfold. Adjust the sliders to see how the outcomes can change. Each line in the charts represents one possible outcome.

Republicans

Including his win in Indiana tonight, Donald J. Trump has won 26 out of the 44 contests so far, and we estimate that he’ll end up with 1,013 delegates when the night is done.

Ted Cruz’s departure from the race leaves a bloc of voters that could go to Mr. Trump or John Kasich. It remains unclear which candidate the Cruz supporters will back, but even if these voters overwhelmingly support Mr. Kasich, it almost certainly won’t be enough to stop Mr. Trump.

Even if Donald J. Trump gets just a quarter of Ted Cruz’s votes, he will win a delegate majority before the convention.

Mr. Kasich would need to win every Cruz voter to have a chance at forcing a contested convention.

Mr. Trump can clinch the nomination by winning 224 of the remaining 445 pledged delegates available in the contests ahead. Just two states — California and New Jersey — account for 223 of these. If we include unpledged delegates who expressed support for Mr. Trump, this figure drops to 183 — about 41 percent of the remaining delegates. Use the table below to explore the most important states on Mr. Trump’s path.

Winning California and New Jersey could be enough for Mr. Trump to secure the Republican nomination.

Click buttons to change state delegate counts Include unpledged delegates who expressed support for Mr. Trump

Mr. Trump is in a very strong position to win enough delegates to secure the Republican nomination. Winning in California and New Jersey — two states where he is polling far ahead of Mr. Kasich — is most likely enough to breach the 1,237-delegate threshold.

There are several caveats that add uncertainty to these numbers. In a few states, there are delegates still to be allocated. Even delegates that have already been allocated can be reassigned.

Mr. Trump’s delegate lead

Democrats

Democratic delegates are awarded proportionally, and in states that have voted so far, Hillary Clinton has won more than half of the vote. The lack of winner-take-all states on the Democratic side makes it very difficult for Bernie Sanders to close the delegate gap.

If Hillary Clinton maintains her current level of support in the remaining races, she will earn a majority of the pledged delegates by June 7.

To have a shot at overtaking Mrs. Clinton in pledged delegates, Mr. Sanders would need a series of landslide victories in the few remaining contests, increasing his vote share to about 70 percent, on average.

Mr. Sanders is also significantly trailing Mrs. Clinton in superdelegates, the roughly 700 Democratic Party officials whose support counts toward the nomination. In past elections, superdelegates have supported the candidate who has received the most pledged delegates, and they are free to switch candidates at any time before the convention in July.

The delegate count as reported by The A.P. lags the total vote somewhat. In the chart below, we have included delegate estimates from The Green Papers, which include the unallocated delegates from states that have already voted.

Mrs. Clinton’s delegate lead