Although it might sound like a buy-one-get-one special at your favorite pizza place, Super Tuesday is one of the most important days in the election cycle.

So what makes Super Tuesday super? 

Twelve states and one U.S. territory are holding their caucuses and primaries, making the day the largest single opportunity for a candidate to win delegates.

Need a refresher or a crash course in democracy? Let’s back up.

General Election

In order to win the presidency, a candidate has to win the general election, held on the Tuesday after the first Monday in November. This is an important distinction from simply the first Tuesday of the month, as the election can never fall on November 1. If you’re thinking it’s because no one would get to the polls the day after a Halloween party, you’re partially right – All Saints Day (November 1) is a holy day of obligation for Roman Catholics, which could impact voter turn-out.

But why a Tuesday?

You have the Congress and farmers of 1845 to thank for this; it’s reported a Tuesday was selected so that voters could travel on Monday in order to observe the Sunday Sabbath and be back home by Wednesday, which was prime time at the markets hawking goods like corn and baskets. November was chosen as it was after the harvest but before the weather turned too treacherous for travel.

Candidates

Our federal laws are fascinating, I know, but enough about that. How does a candidate get to the general election? One of three ways (read more in depth, here): nomination by their political party, run as an independent or as a write-in candidate.

I’m going to focus on the party nomination, since we’re trying to get to how Super Tuesday is just so super important (and oh, it is, and oh, we will get there).

Every one of the Democratic and Republican candidates is currently vying for their party’s nomination, to be announced at their respective conventions. We’ve got two main Democrat contenders: Hillary Clinton and Bernie Sanders. In the other, Republican ring, there are a few more fighters: Ben Carson, Ted Cruz, John Kasich, Marco Rubio and Donald Trump.

Convention

The Democratic National Convention is in Philadelphia at the end of July, the Republican National Convention is scheduled for the week prior in Cleveland.

How do the parties decide on their nominee – their one horse – to send on to the general election? By how the delegates vote. In order to win the Democratic Party nomination, a candidate has to win 2,383 delegates at convention. The Republican candidate has to win 1,237.

Delegates

Alright, fine. So they have to win votes. Got it. But who are these delegates, why are they the ones picking the candidates at the conventions and how does that have anything to do with Super Tuesday?

Each state has a specified number of delegates, allocated by the national parties. That number is determined by what can only be characterized as magic.

Really though, it’s a complicated algorithm for each party that includes factors like how well the state has performed in the past to get their nominees elected, size and number of electoral college votes. The delegates that are chosen to vote at the conventions are picked during either the primary or caucus, depending on what the state or U.S. territory holds.

Read all about the difference between a primary and caucus here.

When a candidate wins a primary or caucus, he or she wins more delegates than the others. There are varying types of delegates and different calculations for how they’re awarded. Albeit a complex process, one fact remains: all of the candidates are racing to get the most number of delegates, the fastest, in order to secure the golden ticket: the party’s nomination.

Putting the Super in Super Tuesday

So what makes Super Tuesday super? The number of delegates up for grabs.

Primaries or caucuses are being held for at least one party (if not both) in Alabama, Alaska, Arkansas, Colorado, Georgia, Massachusetts, Minnesota, Oklahoma, Tennessee, Texas, Vermont, Virginia and American Samoa, all on the same day.

On the Republican side, there are 595 delegates for the taking, which accounts for just under half the number necessary to win the nomination.

Trump leads the field currently with 81 delegates. Cruz and Rubio are down, but not out, tied at 17 each. Kasich and Carson trail with 6 and 4 respectively. With five candidates, the number of delegates could go a variety of ways.

However, if Trump does as well as he did in Nevada and South Carolina, and Cruz and Rubio continue to split votes, Trump could very easily solidify his position as the GOP frontrunner.

For the Democrats, there are 1,004 delegates to win on Tuesday, a little over 40 percent of the total needed. Clinton is coming off a big win in Nevada, boasting 503 delegates to Sanders’ 71. If Clinton wins as decidedly as she is expected to, Sanders might be feeling the burn to suspend his campaign.

Super Tuesday very well could decide our nominees for the general election. Make sure your vote counts.

As you weigh your vote for this election year, what are some questions you need to have answered before you cast your ballot?