What an odds table is trying to show
Most published blackjack odds tables answer a narrow question: if you hold a particular hand and the dealer shows a particular card, what happens on average? The table packs many such answers into a grid so you can look up a situation quickly.
The usual layout is simple:
- Rows are player hands, such as hard 12, soft 18, or a pair of eights.
- Columns are the dealer’s upcard, normally 2 through 10 and ace (ten-valued cards share one column).
- Cells hold a number or set of numbers for that combination.
Once you recognise that structure, most tables, however decorated, are read the same way.
The kinds of numbers you will see
Cells tend to contain one of two kinds of figure.
Outcome probabilities give the chance of winning, losing and pushing the hand if you follow a stated play. Because those three outcomes cover every possibility, they should add up to 100%, give or take rounding. If they do not, check whether the table is leaving out doubles or splits, which can produce larger swings.
Expected value (EV) gives the average result per one unit bet. An EV of -0.20 means that, over a very large number of repeats of that exact situation, you would lose an average of 20 cents per dollar bet. Note that this is an average, not a prediction. In any single hand you will win, lose or push, never “lose 20 cents”.
Here is a purely illustrative example. Suppose a cell reads -0.20 for a particular hand against a particular upcard. Over 10 such hands at $10 each, the average expected result is 10 x $10 x -0.20 = -$20. The actual result of those 10 hands could be anywhere from a clear gain to a much larger loss, because individual outcomes vary far more than the average does. The spread is measured by the standard deviation, and it is large relative to the edge in a short session.
Why a negative number is not an instruction to fold
A beginner’s first surprise is that many cells in a well-built table are negative, even for the best available play. Hard 16 against a ten is the classic case, and hard sixteen gets its own article. The comparison that matters is between the options inside the same cell: if hitting has an EV of -0.54 and standing has an EV of -0.52 (made-up figures for illustration), the table is telling you the choice is nearly even and both lose on average. Choosing the less negative option is the whole idea behind basic strategy.
So when reading a table, compare plays within one row and column rather than judging a cell in isolation.
Reading across and down
Reading across a row shows how the same hand fares as the dealer’s upcard changes. Reading down a column shows how the dealer’s upcard treats different hands. Two patterns usually stand out:
- Cells under dealer 2 through 6 tend to be kinder to the player than cells under 7, 8, 9, 10 and ace. This is the reasoning behind dealer bust cards, where the dealer is more likely to have to draw to a stiff total.
- Stronger hands such as hard 20 show favourable results across almost every column, while hands like hard 12 to 16 are weak in many.
Soft hands, which contain an ace counted as 11, behave differently from hard hands. The soft totals and hard totals have separate sections in most tables because the ace gives you flexibility that changes the bust risk.
The assumptions hiding behind the numbers
Every table is built on assumptions, and they are often written in small print. They matter because the same hand can have a different EV under different rules. Look for:
- Number of decks. A one-deck table and an eight-deck table can differ slightly in a handful of cells. Some tables use an infinite deck, which simplifies the maths by treating each card as independent of the last.
- Dealer drawing rule. Whether the dealer hits or stands on soft seventeen changes figures across the board.
- Doubling, splitting and surrender options. A table that allows these will give different numbers from one that does not.
- Hole card handling. Whether the dealer checks for a natural before the player acts affects the cells for ten and ace upcards.
- Natural payout. Cells that include naturals depend on whether the table pays 3 to 2 or 6 to 5.
If a table does not state its assumptions, treat its numbers as rough guidance only. A figure you cannot place under a rule set is not very useful.
How these tables are produced
Tables are generated either by exact enumeration, which counts every possible sequence of cards, or by computer experiments run over millions of simulated hands. The method behind simulated tables is explained under simulation basics. Simulated figures carry a small margin of error, so two sources may differ in the third decimal place without either being wrong.
What a table cannot tell you
An odds table describes long-run averages for a fixed situation. It does not say what the next card will be, it does not account for cards you have already seen unless it is explicitly built that way, and it cannot make a session profitable. Blackjack has a house edge even when every decision is optimal, and no chart alters that.
Treat tables as a way of understanding why certain plays are recommended, not as a way of predicting or controlling results. Gambling can cause harm, outcomes are uncertain, and if it is affecting your life, a local support service can help.