The Odds of Getting Blackjack Using a Single Deck is Roughly 4.8%
April 23rd, 2017 8:52 pm ESTOne of the questions that we receive most often via our inbox  what are the odds of hitting blackjack using a single deck?
The answer to the question is roughly 4.8%. Let's break down the calculations to show you how you would arrive at this number.
First off, there are 52 cards in a single deck of cards. The first card that you draw, you have a total of 52 different possibilities as to what the card could be. After drawing the first card, you draw the second card, and there are 51 possibilities for what that card could be (as you have removed one of the possibilities from the deck, as it is currently in your hand).
So, there are a total of 2,652 different combinations that you could have as your first two cards (52 * 51).
Of the total combinations in the deck, there are 128 combinations in which you will be dealt an Ace followed by a 10 or a 10 followed by an Ace. This is obviously a Blackjack.
So, there are 128 Blackjack possibilities in a deck that could produce a total of 2,652 different combinations.
So, based on these numbers, there is a 4.826546003% chance that you will hit a Blackjack every time that a single deck is dealt. This number is arrived at by dividing 128/2,652.

Note: these odds assume that the deck is randomly shuffled