How the Odds Work in Online Blackjack

With perfect basic strategy and standard online rules, the house keeps about 0.62% of each bet over many hands, and you get a paid blackjack about once every 22 hands. The dealer busts most often with a 6 showing (43.9%) and least often with an ace (13.9%), and the house keeps its edge because you act first and lose right away if you bust.

• The House Edge in One Line
• Why the House Has an Edge
• Dealer Bust Chances by Up Card
• How Often You Get a Paid Blackjack
• How Rules Change the Odds
• What the Odds Mean Over a Session

01The House Edge in One Line

The house edge is the share of each bet the casino keeps on average over many hands.

With perfect basic strategy and standard rules, the house edge is about 0.62%.

• Basic strategy is the chart of best moves for every hand against every dealer up card.
• The up card is the dealer's card you can see.
• Standard rules are 6 decks, dealer hits soft 17, double after split allowed, no surrender, dealer peeks for blackjack, and blackjack pays 3:2.

Here your hand is 10 and 7, a total of 17. The dealer's up card is a 6.

The chart row below shows the move for hard 17 against every up card: stand.

Victoria's tip

Keep the basic strategy chart open while you play. Every move that is not on the chart raises the house edge.

02Why the House Has an Edge

You play your hand before the dealer. If your total goes over 21, you bust and lose your bet right away.

The dealer can bust later in the same round, but your bet is already gone. This is where the house edge comes from.

• You bust first, so you lose even when the dealer busts later in the round.
• You get some things back: a blackjack pays you 3:2, while a dealer blackjack only takes your bet.
• You can double down (double your bet and take one card) and split pairs (two cards of the same value). The dealer cannot.
• You can stand on any total. The dealer must hit until reaching 17 or more.

Hard 16 against a dealer 10 loses money on average whatever you do. A hard hand has no ace counted as 11.

A minus sign means you lose that share of your bet on average. Hitting loses a little less, so the chart says hit against a 10.

03Dealer Bust Chances by Up Card

The dealer must hit until reaching 17 or more. On standard rules the dealer also hits soft 17, a 17 that counts an ace as 11.

An ace counts as 11 unless that would bust the hand. Then it counts as 1.

These numbers are for 6 decks with the dealer hitting soft 17, counted before the dealer checks for blackjack. If the dealer stands on soft 17, a 6 busts 42.3% of the time.

With a 2 to 6 showing, the dealer busts most often. That is why the chart tells you to stand on hard 13 against those cards.

You can check other up cards and rules in the dealer bust calculator.

04How Often You Get a Paid Blackjack

A blackjack is an ace plus a ten-value card (10, J, Q or K) as your first two cards.

A paid blackjack comes about once every 22 hands. That is 4.53% of all hands.

Paid means the dealer did not also have a blackjack. When both have one, the hand is a tie, called a push, and you get your bet back.

The picture shows what a 10 bet pays at each ratio. The ratio changes the house edge a lot.

• Blackjack pays 3:2: house edge 0.62%.
• Blackjack pays 6:5: house edge 1.98%. That adds 1.36 percentage points. See 6:5 blackjack.
• Blackjack pays 1:1: house edge 2.88%.

Victoria's tip

Read the table sign before your first hand. If it says blackjack pays 6:5, look for a table that pays 3:2.

05How Rules Change the Odds

Small rule changes move the house edge. Each row below changes one or two rules from the standard game.

Late surrender means you give up half your bet after the dealer checks for blackjack. No-hole-card means the dealer takes a second card only after you play.

This dealer hand is soft 17. When the dealer hits soft 17, the dealer takes another card here.

• Dealer hits soft 17 adds 0.21 percentage points.
• No double after split adds 0.14 percentage points.
• Double on 10 and 11 only adds 0.20 percentage points.
• Late surrender lowers the edge by 0.09 percentage points.

Enter the rules of any table in the house edge calculator to see its number.

06What the Odds Mean Over a Session

The house edge is an average over a very large number of hands. In one session, your result can be far above or far below it.

• Average is what the house keeps per bet over a very long run: about 0.62% with basic strategy.
• Spread is how far one session moves away from the average. Over a short session, the spread is much bigger than the edge.
• Mistakes raise the average. Every move that is not on the chart costs you a little.

The table shows a $10 bet on every hand with basic strategy and standard rules.

After one hundred hands at $10, about 9 sessions in 10 end within $191 of the average. The more hands you play, the smaller your chance of being ahead.

Basic strategy lowers the house edge. It does not remove it, and over many hands the house keeps its share.

Victoria's tip

Play a few thousand hands in the blackjack simulator to see how results swing around the average. Set a time and money limit before you play for real.

Read the responsible gambling page for help with limits.

Questions people ask