Blackjack calculator: the best move and what every option returns
Pick your two cards and the dealer's up card. The calculator works out the expected return of every legal move, exactly, and shows which one loses least or wins most over time.
Expected return of each move, as a share of your original stake
How the dealer finishes with 10 showing
With a ten showing, the dealer has blackjack 7.69% of the time and checks before you act; the figures above are for the hands that go on. House edge of these rules with perfect play: 0.57%.
How to use the blackjack calculator
Choose your first card, your second card and the dealer's face-up card. A 10, jack, queen and king all count as ten, so they share one button. Then set the four table rules to match the game in front of you: whether the dealer stands or hits on soft 17, whether a blackjack pays 3:2 or 6:5, whether you may double after splitting and whether late surrender is offered. They are printed on the felt or in the game's help screen.
The large figure is the best move. Below it, every option on the table has its expected return, and the dealer's chances of finishing on each total or busting sit underneath. If a move is not possible, such as splitting a hand that is not a pair, it is marked n/a with the reason. The figures change as soon as you pick a different card or rule, and nothing you enter leaves your browser.
What the expected return means
Expected return is the average result of a move, as a share of the stake you started the hand with, over a very long run of identical hands. A figure of −21% means that, on average, you lose 21p for each £1 staked each time you make that play in that spot. A positive figure means the hand is in your favour: 11 against a dealer 6, for instance, is a hand you want to have. Most hands in blackjack have a negative return whatever you do, and the task is to choose the move that loses least.
Doubles and splits are measured against your original stake too, even though they put a second stake on the table. That is why a double can show a figure below −100%: when you double a hand that is more likely to lose than win, you can lose up to twice what you started with.
When the dealer shows an ace or a ten, they check for blackjack before you act, and the figures in the calculator are for the hands that carry on after that check. With a 10 showing the dealer turns up blackjack 7.69% of the time, and with an ace 30.77%.
Worked examples
The four hands below cover the decisions players most often get wrong. Each figure comes from the same calculation the tool runs, on the standard table: dealer stands on soft 17, doubling after a split allowed, no surrender, 3:2.
| Hand | Stand | Hit | Double | Split | Best move |
|---|---|---|---|---|---|
| Hard 16 (10,6) v 10 | −54.04% | −53.98% | −107.97% | n/a | Hit |
| Hard 11 (5,6) v 6 | −15.37% | +33.37% | +66.74% | n/a | Double |
| Soft 18 (A,7) v 9 | −18.32% | −10.07% | −29.02% | n/a | Hit |
| 8,8 v 10 | −54.04% | −53.98% | −107.97% | −48.95% | Split |
Hard 16 against a 10
Standing returns −54.04%, because a dealer 10 busts only 23.0% of the time and otherwise always beats 16. Hitting returns −53.98%: you bust often, but a small card gives you a hand that can win. The gap is just 0.06% of a stake, so either choice is a poor hand, but hitting is the better one. On a table with late surrender, giving up half the stake at −50% beats both, and the calculator switches its answer to surrender.
Hard 11 against a 6
Standing on 11 would be a mistake at −15.37%, since you could only win by the dealer busting. Hitting returns +33.37%, but doubling returns +66.74% of the original stake, twice as much, because a ten-value card is the most likely next card and the dealer 6 busts 42.3% of the time.
Soft 18 (ace and 7) against a 9
Many players stand on 18, but against a 9 it is not good enough: the dealer finishes on 19 or more most of the time, and standing returns −18.32%. Because the ace can drop back to 1, hitting a soft 18 cannot bust on the next card, and it returns −10.07%. Hitting is the better move by 8.24% of a stake, one of the larger gaps among the hands players get wrong.
A pair of 8s against a 10
Sixteen is the worst total in blackjack, and a pair of 8s is a 16. Standing returns −54.04% and hitting −53.98%. Splitting turns one terrible hand into two hands that each start on 8, and returns −48.95% across both stakes. It still loses on average, but it loses less, which is why the rule is to always split 8s. Even with late surrender available, splitting remains a little better than giving up half the stake.
Reading the dealer's outcome
The bars under the moves show how the dealer's hand is likely to finish for the up card you chose, once blackjack has been ruled out. The dealer has no choices, so the final total is pure probability. A dealer 5 or 6 busts more than 40% of the time, which is why you stand on stiff totals and double more often against them. A dealer 10 or ace rarely busts, which is why you need a strong total to stand.
Changing the soft 17 rule changes the bars for low up cards and for an ace, where a soft 17 is a common way for the dealer to finish. The full grid for every up card, with the bust chance for each, is on the blackjack odds page.
How the calculator works
The calculator solves each hand exactly rather than simulating it. For the dealer's up card, it first works out the chance of every final dealer total. It then goes through every card you could draw, and every card after that, choosing the best of standing or hitting at each step, until each path ends in a stand or a bust. Doubling takes exactly one card; a split plays each new hand the same way, with split aces taking one card each and no resplitting. The method is described in full on the how we calculate the odds page.
All of this uses an infinite deck, where every rank keeps a 1 in 13 chance on every draw and a ten-value card 4 in 13. Real shoes differ very slightly, because each card dealt changes what is left. In a few borderline hands, such as 16 against a 10, that can tip a finite shoe the other way. For almost every hand, and for anything dealt from a freshly shuffled shoe, the infinite-deck answer is the right one.
Put the best move for every hand together and you get the house edge of the table: 0.57% on the standard rules, as the note under the results shows for any rules you choose. The house edge page explains how that compares with other games, and the roulette odds calculator and poker odds calculator do the same job for those games.
Knowing the best move keeps the cost of blackjack as low as it can go, but it never turns the game in your favour. If you are playing more often or for longer than you meant to, you will find free support on our responsible gambling page.
Keep reading
Blackjack calculator: questions people ask
What does the blackjack calculator show?
For any two starting cards and any dealer up card, it shows the expected return of standing, hitting, doubling, splitting and surrendering, marks the best of them, and shows how the dealer's hand is likely to finish. Change a table rule and every figure updates.
What does an expected return of −54% mean?
It is the average result of that move, as a share of your stake, over a very large number of identical hands. At −54% you would lose about £54 for every £100 staked on that hand in the long run. It does not mean you lose 54p on each hand: each hand is won, lost or pushed in full.
Why are doubles and splits sometimes shown below −100%?
Because they put more money on the table. The calculator measures every move against your original stake, so a double that loses more often than it wins can cost up to twice the stake. A −108% double means you would lose, on average, a little more than your original stake by doubling.
Is the calculator the same as basic strategy?
It is where basic strategy comes from. A basic strategy chart is a summary of the best move for each hand; the calculator shows the numbers behind each cell, including how close the second-best move is. The full chart is on the blackjack odds page.
Does the calculator know which cards have already been dealt?
No. It uses an infinite deck, where every card keeps the same chance on every draw. That matches digital games that shuffle every hand, and sits very close to a six- or eight-deck shoe. It does not track a shoe as it is dealt, so it cannot be used for counting.
Why does the calculator say hit 16 against a 10?
Because standing is slightly worse. Standing on 16 wins only if the dealer busts, which a dealer 10 does 23.0% of the time. Hitting returns −53.98% against −54.04% for standing, a gap of 0.06% of a stake. With late surrender offered, surrendering at −50% beats both.
Does the dealer check for blackjack in these figures?
Yes. With a 10 showing the dealer has blackjack 7.69% of the time, and with an ace 30.77%. The dealer checks before you act, so the figures are for the hands that go on after the check, which is when your decision matters.
Does a bigger stake change the best move?
No. Expected return is a share of the stake, so the best move is the same at £1 or £100; only the average win or loss in pounds grows.
Which rule makes the biggest difference?
The payout on a blackjack. On otherwise standard rules, a 6:5 payout lifts the house edge from 0.57% to 1.92%. It does not change the best move for any hand, because a natural is paid before any decision.