Which mistake should I fix first?
Standing on 15 and 16 against strong dealer cards, because it is both the most frequent and among the most expensive. Then doubling, which is the biggest single source of missed value.
Guru
Blackjack Beginner Mistakes And How To Fix Them
Updated
Most of the money beginners lose at blackjack beyond the house edge comes from a short list of repeated errors, not from hundreds of small ones. Fixing the eight below takes a typical intuitive player from around 2 percent to under 0.7 percent, which is the difference between an expensive hobby and a cheap one.
This guide is about strategy errors at the table. The most common mistakes guide on this site covers the behavioural and table-etiquette mistakes that cost players in other ways.
Mistakes with stiff hands
Standing on 15 or 16 against a 7 or higher is the most frequent error and costs about 4 cents per dollar each time. The fix is purely mechanical: against 7 through ace, any hard total of 16 or less hits. Say it before you act.
Hitting 12 against a 4, 5 or 6 is the mirror image, driven by '12 is not a hand'. Against those three cards the dealer busts about 40 percent of the time and you stand. Hitting 13 through 16 against a 2 or 3 is the same mistake in a different spot; those also stand.
Mistakes with doubles and splits
Not doubling 11, 10 and 9 in the right spots, and never doubling soft hands, together cost about 1.5 percent of total action. Beginners under-double because a lost double hurts twice as much. The fix is to treat the chart's doubles as mandatory, not optional, and to size bets so a double is always affordable.
Splitting 10s against a weak dealer and not splitting 8s against a strong one are the two most expensive splitting errors. Both come from thinking about the hand you have rather than the hands you would make. Pairs of 10s stand; pairs of 8s split; there are no exceptions in basic strategy.
Mistakes with soft hands
Standing on soft 17 and standing on soft 18 against a 9 or 10 are the signature soft-hand errors. Both come from reading the total and forgetting the ace. Soft 17 is never a standing hand; soft 18 stands only against 2, 7 and 8 (and the ace under S17).
Doubling soft 19 against a 6 is the opposite error, made by players who have learned 'double soft hands against a 6' as a slogan. Soft 19 and 20 always stand.
Mistakes that are not about the cards
Taking insurance or even money costs about 7 percent of every insurance bet and is probably the most widespread error among otherwise competent players. Playing at a 6:5 table costs 1.4 percent of every bet before you have made a decision. Raising your bet after losses to 'get even' turns a small negative expectation into a large one with a real risk of ruin.
None of these can be drilled in a trainer because they happen before the cards come out. They are decisions you make at the door: read the felt, decline insurance by default, and set your bet size from your bankroll before you sit down.
Beginner Mistake Correction Map
| Mistake | Approx Cost | Correct Play | Drill |
|---|---|---|---|
| Standing on 15-16 vs 7-A | 4 cents per $1, each time | Hit | Common Mistake Training, hard totals |
| Hitting 12 vs 4-6 | 2-3 cents per $1 | Stand | 100 hands of 12 vs weak dealer |
| Never doubling | 1.5% of total action | Double per chart | Flashcards for 9, 10, 11 and soft 13-18 |
| Splitting 10s | Up to 15 cents per $1 vs a 6 | Stand | Repeat 'twenty stands' before acting |
| Not splitting 8s | 6+ cents per $1 | Split | 8,8 vs every upcard, 50 reps |
| Standing on soft 17-18 vs 9-10 | 3-4 cents per $1 | Hit | Soft total drill, dealer 9 and 10 only |
| Taking insurance / even money | About 7% of the side bet | Decline | None needed; decide once |
| Playing 6:5 tables | 1.4% of every bet | Find a 3:2 table | Read the felt before sitting |
FAQ
Do these mistakes matter if I am still winning?
Yes. Short-term results are mostly luck. A player making these errors is paying about four times the house edge of a correct player, and that bill arrives over time whether or not any given session is a winner.
How do I know which mistakes I personally make?
Play fifty hands in the trainer with an account and open the hand history. It lists every decision that deviated from basic strategy and roughly how much each cost.
Related Guides
Practice This In The Trainer
Reading strategy helps, but repetition is what locks it in. Use the trainer to practice hand-by-hand decisions with immediate EV-focused feedback.