Blackjack Odds and House Edge: The Numbers Behind Basic Strategy
Blackjack house edge is about 0.5% with basic strategy and 2% or more without. Odds of winning a hand, dealer bust rates by up-card and RTP explained.
Every claim on this site about basic blackjack strategy rests on a handful of probabilities: how often the dealer busts from each up-card, how often you bust when you take a card, and what each rule is worth. This page lists them. The figures are approximate, assume a six-deck shoe and basic strategy unless stated otherwise, and are long-run averages. No strategy guarantees a win on any hand or in any session; what these numbers describe is what happens over many thousands of hands.
House edge with basic strategy
The headline: on a typical UK six-deck game (dealer stands on soft 17, double on any two cards, double after split allowed, no surrender, no hole card, blackjack pays 3:2), basic strategy gives a house edge of about 0.5%. For every £100 wagered over the long run, the expected loss is about 50p.
How the hand is played matters more than any single rule:
| How you play | House edge (UK six-deck rules) | Expected loss per £1,000 wagered |
|---|---|---|
| Casual play from instinct, no chart | around 2% or more | £20 or more |
| Basic strategy from the chart | about 0.4% to 0.5% | £4 to £5 |
| Perfect composition-dependent play | roughly 0.01% to 0.04% better than basic strategy | about £3.60 to £4.90 |
The 0.4% figure applies when the dealer takes a hole card and checks for blackjack; the 0.5% figure is the UK no hole card game, where a double or split stake is also lost to a dealer blackjack. The UK blackjack strategy guide explains the five chart changes that follow from that.
The third row is worth a sentence because people ask whether there is something better than basic strategy. There is, and it is worth a few hundredths of a per cent: composition-dependent play looks at the exact cards in your hand rather than the total, and the perfect strategy page sets out the handful of hands where it differs. The gap between casual play and basic strategy is around 1.5 percentage points. The gap between basic strategy and perfect play is around 0.03. Learn the chart first.
House edge by rule
Starting from a six-deck, S17, DAS, no surrender, hole card game at about 0.4%, each rule variation moves the figure by roughly the amount shown. All with basic strategy.
| Rule variation | Effect on house edge | Resulting edge (from 0.4% base) |
|---|---|---|
| Late surrender offered | about 0.07% better | about 0.33% |
| No hole card (UK standard) | about 0.1% worse | about 0.5% |
| Dealer hits soft 17 (H17) | adds about 0.2% | about 0.6% |
| Blackjack pays 6:5 instead of 3:2 | adds about 1.4% | about 1.8% |
| No double after split | adds about 0.14% | about 0.54% |
| Double only on 10 and 11 | adds about 0.18% | about 0.58% |
| No resplitting | adds about 0.1% | about 0.5% |
| 8 decks instead of 6 | adds about 0.02% | about 0.42% |
| Double deck (3:2, S17, DAS) | lower | about 0.3% to 0.35% |
| Single deck (3:2, S17, DAS) | lower | about 0.15% to 0.2% |
| Continuous shuffling machine | about 0.02% better | about 0.38%, but more hands an hour |
Three things to take from the table. First, a 6:5 blackjack payout is in a category of its own: it costs more than every other bad rule added together, and a single-deck game at 6:5 is worse than a standard shoe at 3:2. Second, the number of decks matters far less than people assume once you are past two: six against eight is two hundredths of a per cent. Third, the effects stack, so an eight-deck H17 game with no DAS and doubling restricted to 10 and 11 is sitting at around 0.9% before you have made a mistake. The blackjack strategy charts has the correct chart for each of these rule sets, because the best play changes with the rules as well as the edge.
Odds of winning a hand
Playing basic strategy in a six-deck game, a single hand resolves roughly as follows:
| Outcome | Probability |
|---|---|
| Win | about 42% |
| Lose | about 49% |
| Push | about 9% |
You lose more hands than you win. The house edge is only 0.5% rather than 7% because the hands you win are, on average, worth more: blackjacks pay 3:2, and doubles and splits put extra money on the hands where you hold the advantage. Setting pushes aside, you win about 46 of every 100 decided hands.
Some other single-hand figures that come up constantly:
| Event | Probability |
|---|---|
| You are dealt a natural blackjack | about 4.75% (roughly 1 hand in 21) |
| Dealer has blackjack when showing an ace | about 31% |
| Dealer has blackjack when showing a ten | about 8% |
The 31% figure is the whole case against insurance. Insurance pays 2 to 1 on the dealer having a ten under the ace. The true odds against it in a six-deck game are roughly 2.2 to 1, and that gap gives the insurance bet a house edge of around 7%, fourteen times the edge on the main hand. The 8% figure is why standing on a stiff hand against a dealer ten is not "giving up": the dealer does not have blackjack 92% of the time, and still makes a hand of 17 or better far more often than not.
Dealer bust probability by up-card
This is the table the whole of basic strategy is built on. The dealer plays by a fixed rule (here, stand on soft 17) and these are the chances of busting from each up-card, after the check for blackjack:
| Dealer up-card | Dealer bust probability |
|---|---|
| 2 | about 35% |
| 3 | about 37% |
| 4 | about 40% |
| 5 | about 42% |
| 6 | about 42% |
| 7 | about 26% |
| 8 | about 24% |
| 9 | about 23% |
| 10 | about 23% |
| A | about 17% |
Up-cards 2 to 6 are called weak because the dealer busts between a third and well over two fifths of the time from them, and that is why basic strategy stands on hard 13 to 16 against all of them and doubles and splits more aggressively into them. Up-cards 7 to A are strong because the dealer makes a hand roughly three times in four, so you have to make one too, which is why the chart hits 12 to 16 against them.
The jump between 6 (42%) and 7 (26%) is the most important line on this page. Against a 6 the dealer is a coin flip to bust; against a 7 they make a hand three quarters of the time. A hard 12 is a stand against the 6 and a hit against the 7 for exactly that reason, and the same cliff is behind the double on 9 against 3 to 6 but not against 7.
Two notes on the figures. A 2 and a 3 are weaker than a 4 to 6 but still bust-prone enough to stand on 13 or more; 12 is the exception (hit against 2 and 3) because 12 busts on any ten and the dealer's 35% is not quite high enough to justify sitting on it. And if the dealer hits soft 17, the bust probabilities from an ace and a 6 rise slightly but the dealer's final hands improve more, which is where the extra 0.2% house edge comes from.
Player bust probability by total
The other side of every hit-or-stand decision. These are the chances of busting if you take exactly one more card on a hard total:
| Your hard total | Bust probability on the next card |
|---|---|
| 12 | about 31% |
| 13 | about 39% |
| 14 | about 56% |
| 15 | about 58% |
| 16 | about 62% |
| 17 | about 69% |
| 18 | about 77% |
| 19 | about 85% |
| 20 | about 92% |
Put the two tables together and basic strategy falls out. Hard 16 against a dealer 10: hitting busts you 62% of the time, but standing only wins when the dealer busts, which is 23%, so hitting is the lesser evil (and surrendering, where allowed, is better than both). Hard 16 against a dealer 6: standing wins 42% of the time outright, which beats a 62% chance of busting, so you stand. Hard 12 against a 4: you bust 31% of the time by hitting and the dealer busts 40% of the time if you stand, so standing is right, but only just, which is why 12 is the hand people argue about.
The 17 to 20 rows explain why you never hit a hard 17 or above: the bust rate is 69% and up, and the dealer's own hand is finishing on 17 or better most of the time anyway. The blackjack hand calculator gives the expected value of each option for any hand under any rules if you want the full working rather than the summary.
RTP vs house edge
Online games tend to quote RTP (return to player) rather than house edge. They are the same number from two directions:
RTP = 100% minus house edge. House edge = 100% minus RTP.
| Game and play | House edge | RTP |
|---|---|---|
| UK six-deck, basic strategy | about 0.5% | about 99.5% |
| Six-deck with hole card and late surrender, basic strategy | about 0.33% | about 99.67% |
| Six-deck, dealer hits soft 17, basic strategy | about 0.6% | about 99.4% |
| Six-deck, blackjack pays 6:5, basic strategy | about 1.8% | about 98.2% |
| Any rules, casual play | around 2% or more | around 98% or less |
| Free Bet Blackjack, correct strategy | about 1.0% | about 98.5% |
The catch is in the last column of every game information panel: the quoted RTP assumes basic strategy. A game listed at 99.5% is not paying 99.5% to a player who stands on 16 against a 7 and takes insurance; that player is somewhere around 98%. The RTP is the ceiling for the rules, and your play decides how far below it you sit. It is also a long-run figure: over an hour, your personal return will be nowhere near 99.5% in either direction.
Where providers publish several RTP figures for the same game (for instance one for the main bet and another for a side bet), the side bet figure is always lower, usually by several percentage points. Perfect Pairs runs at about 4% to 6% house edge (94% to 96% RTP) and 21+3 at about 3% to 7%. The online blackjack strategy guide covers how to read a game panel before playing.
Expected loss worked example
House edge becomes money through one formula:
Expected loss = house edge x total amount wagered.
Take a player betting £10 a hand at 60 hands an hour, which is £600 wagered per hour:
| House edge | Who this is | Expected loss per hour | Per 5-hour session | Per 100 hours |
|---|---|---|---|---|
| 0.5% | Basic strategy, UK six-deck | £3 | £15 | £300 |
| 1% | A few regular mistakes, or a 6:5 table played well | £6 | £30 | £600 |
| 2% | Casual play from instinct | £12 | £60 | £1,200 |
Over 100 hours, the difference between knowing the chart and not knowing it is around £900 at £10 stakes. That is the entire case for the free blackjack strategy trainer.
The usual caveat applies with force here. "Expected loss of £3 an hour" does not mean you will be £3 down after an hour. At £10 stakes the typical swing in an hour is tens of pounds either way, and being £100 up or £100 down is unremarkable. The expectation only shows itself over many hours, which is why the long-run figures in the right-hand column are the ones that matter for budgeting and the hourly figure is the one that matters for deciding whether the stake is right. Betting systems do not alter any of this; they move the money between hands without changing the total, as the betting strategy page shows hand by hand.
Frequently asked questions
What are the odds of winning a hand of blackjack?
With basic strategy in a six-deck game, about 42% of hands win, 49% lose and 9% push. You win fewer hands than you lose, and the house edge is still only about 0.5% because blackjacks pay 3:2 and doubles and splits add stake to the hands where you hold the advantage.
What is the house edge without basic strategy?
Around 2% or more for a typical casual player, against about 0.5% with basic strategy on UK six-deck rules. The exact figure depends on which mistakes you make and how often, but standing on stiff hands against high cards, skipping doubles and taking insurance are the usual sources. At £10 a hand that gap is about £9 an hour.
Does the house edge change online?
The rules set the edge, not the venue. Online games often have slightly better rules than land-based tables and always publish them, so the edge can be a little lower. They also deal more hands an hour, so the expected loss per hour can be higher at the same stake. RNG games reshuffle every hand, which has no effect on the basic strategy edge but makes counting impossible.
What are the best odds in a casino?
Blackjack with basic strategy at about 0.5% is among the lowest house edges on any casino floor, and a single-deck 3:2 game at around 0.15% to 0.2% is lower still. The same table's side bets, at 3% to 7%, and insurance at around 7%, are among the worst. The edge only applies if you play the chart; without it, blackjack is no better than most other games.
What is blackjack RTP?
RTP is return to player, the percentage of all money wagered that is paid back over the long run. It equals 100% minus the house edge, so a UK six-deck game with basic strategy has an RTP of about 99.5%. Quoted RTP figures assume basic strategy; playing by instinct lowers your personal return to around 98% or below.
How often does the dealer bust?
It depends on the up-card. With the dealer standing on soft 17, the bust rate runs from about 17% with an ace showing to about 42% with a 5 or 6, with 2 to 6 all at 35% or higher and 7 to ace all at 26% or lower. Across all up-cards combined the dealer busts a little under three hands in ten.
Back to Blackjack strategy: basic strategy explained, with the full chart