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Lesson 5.2 Money and time
Why Your Blackjack Sessions Swing Up and Down
After this lesson you will know why one session of online blackjack can end far up or far down, and how wide that spread is after a hundred hands at $10. You will also see why your chance of being ahead shrinks the longer you play.
Each hand moves your balance by a different amount
In a normal hand you win or lose your bet. Some hands put more money on the table.
- Win or lose – you are paid 1:1 or you lose the bet.
- Blackjack – an ace and a ten-value card as your first two cards, paid 3:2.
- Double down – you double your bet and take exactly one more card.
- Split – you turn a pair (two cards of the same value) into two hands, each with its own bet.
| 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | A |
|---|---|---|---|---|---|---|---|---|---|
| D | D | D | D | D | D | D | D | D | D |
With standard rules (dealer hits soft 17), the chart says double hard 11 against every dealer up card. That doubles what this hand can win or lose.
| 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | A |
|---|---|---|---|---|---|---|---|---|---|
| P | P | P | P | P | P | P | P | P | P |
The chart says split a pair of 8s against every dealer up card. Now two bets are on one deal.
In our simulation, the standard deviation of one hand – how far a result usually lands from the average – is about 1.16 bets.
After a hundred hands: the swing is bigger than the house edge
Take a hundred hands at $10 a hand with basic strategy and standard rules. The house edge – the share of each bet the house keeps on average – costs you about $6.17.
| A hundred hands at $10 | Amount |
|---|---|
| Average loss | $6.17 |
| About 9 sessions in 10 end within this much of the average | $191 |
The swing is much larger than the average loss. A session can end well ahead or well behind, and both results are normal.
A good or bad session of a hundred hands says almost nothing about how you played. Check your moves against the strategy chart, not against your balance.
More hands: the average takes over
The average loss grows in step with the number of hands. The swing grows more slowly.
Over many hands, the house edge becomes the bigger part of your result.
| Hands played | Chance of being ahead |
|---|---|
| A hundred | 48% |
| A thousand | 43% |
| Ten thousand | 30% |
After a hundred hands you are ahead in close to half of sessions. After ten thousand hands that falls to 30%.
You can watch this happen in the blackjack simulator.
What to do with the swings
- Pick a session budget that covers the swing, not just the average loss.
- Keep playing the chart after a losing streak. A streak does not change the right move.
- Do not raise your bets to win back losses. Bigger bets make the swing bigger and do not change the house edge. See blackjack betting systems.
- Set a time limit as well as a money limit. Read the responsible gambling page.
Hard 11 against a dealer 9: the chart says double. This hand puts two bets on one deal.
Practice the double and split hands in the trainer below. They are the hands that put the most money on one deal.
Practise: 25 hands
Only hands from this lesson. Your first answer counts.
The lesson on one card
- One hand can move your balance by one bet, two bets or more.
- Doubles and splits put extra bets on the table and make swings bigger.
- After a hundred hands at $10, about 9 sessions in 10 end within $191 of the average.
- Chance of being ahead: 48% after a hundred hands, 30% after ten thousand.
- Short sessions are mostly swing. Long play is mostly house edge.
- Judge your play by the chart, not by one session's result.
Check yourself
1. Why can one hand of blackjack change your balance by more than one bet?
Doubles and splits put extra bets on the same deal.
Right. When you double or split, you add a second bet. That hand can then win or lose more than one bet.
The dealer takes your bet twice when you lose.
Not quite. A losing hand loses only the money you placed on it. Extra losses come from extra bets you added by doubling or splitting.
Every winning hand pays 3:2.
Not quite. Only a blackjack pays 3:2. A normal winning hand pays 1:1.
2. You keep playing basic strategy with the same rules. What happens to your chance of being ahead as you play more hands?
It falls, from 48% after a hundred hands to 30% after ten thousand hands.
Right. The average loss grows faster than the swing. Over many hands the house edge decides more of the result.
It stays the same, because each hand is separate.
Not quite. Each hand is separate, but the losses add up. The swing does not grow as fast as the average loss, so the chance of being ahead drops.
It rises, because good play shows over time.
Not quite. Basic strategy lowers the house edge but does not remove it. Over time the remaining edge pulls your result down.
3. A friend plays a hundred hands at $10, ends ahead, and says his new betting pattern works. What does this lesson tell you?
His result fits inside the normal swing, so it proves nothing about the pattern.
Right. About 9 sessions in 10 end within $191 of the average, so ending ahead after a hundred hands is common. A betting pattern does not change the house edge.
It proves the pattern removes the house edge.
Not quite. One short session is mostly swing. The house edge stays the same whatever pattern of bets you use.
He should expect to end ahead in his next session too.
Not quite. Each session swings on its own, so the next hundred hands can end up or down. Over many hands the average loss takes over.