How to use this page
This page is a reference, not a tutorial. It collects the numbers and definitions that come up most often when discussing blackjack, in tables you can scan. Every figure is a standard arithmetic result or a plain rule; where a value depends on the table, the page says so. Nothing here describes a way to win: blackjack has a house edge, and results in any session are uncertain.
Card values
| Card | Value in blackjack |
|---|---|
| 2 to 9 | Face value |
| 10, jack, queen, king | 10 |
| Ace | 1 or 11, whichever is better without going over 21 |
Suits have no effect on the hand total under ordinary rules. The full explanation of how totals are formed is in the article on basic hand values.
Composition of a deck
| Item | Count |
|---|---|
| Cards in one deck | 52 |
| Ten-value cards | 16 |
| Aces | 4 |
| Cards worth 2 to 9 | 32 (four of each rank) |
| Share that are ten-value | 16/52 = about 30.8% |
| Share that are aces | 4/52 = about 7.7% |
Total cards by number of decks
| Decks | Total cards | Ten-value cards | Aces |
|---|---|---|---|
| 1 | 52 | 16 | 4 |
| 2 | 104 | 32 | 8 |
| 6 | 312 | 96 | 24 |
| 8 | 416 | 128 | 32 |
The proportions stay the same in every row. What changes is how much one dealt card shifts the remaining mix.
Two-card hands
| Quantity | Value |
|---|---|
| Ordered ways to deal two cards from one deck | 52 × 51 = 2,652 |
| Distinct two-card hands (order ignored) | 1,326 |
| Ace plus ten-value combinations | 4 × 16 = 64 |
| Chance of a natural from one fresh deck | 64/1,326 = about 4.8% |
| Chance the second card matches the first rank (one deck) | 3/51 = about 5.9% |
Natural payouts
The payout for a natural varies by table, which is why it is worth checking before you sit down. For an illustrative bet of 10 units:
| Payout | Winning natural pays | Returned with stake |
|---|---|---|
| 3 to 2 | 15 units | 25 units |
| 6 to 5 | 12 units | 22 units |
The difference is 3 units on every natural for a 10-unit bet, which adds up over many hands. The topic is covered in detail under natural payouts.
Common dealer rules
| Rule | What it means |
|---|---|
| Dealer draws to 16 | The dealer must keep taking cards on any total of 16 or less |
| Dealer stands on 17 | The dealer stops on hard 17 or higher |
| Soft 17 | Some tables have the dealer hit a total of 17 that includes an ace counted as 11; others stand. The wording is posted on the table layout |
The difference between these two versions is explained under soft seventeen, and the wider set of dealer procedures falls under dealer drawing rules. A hard total has no ace counted as 11; a soft total does.
Glossary
- Natural (blackjack): An ace and a ten-value card as the first two cards.
- Push: A tie with the dealer; the stake is returned.
- Bust: A hand total over 21, which loses.
- Hit / stand: Take another card / keep your current total.
- Double down: Double the bet in exchange for exactly one more card.
- Split: Divide a pair into two separate hands, each with its own bet.
- Upcard: The dealer card that is face up.
- Shoe: The container holding several decks that are dealt from.
- Penetration: How far into the shoe the dealer deals before reshuffling.
- House edge: The average amount the casino keeps, as a percentage of the amount wagered, over a very long run.
- Expected value: The probability-weighted average result of a bet.
- Variance: A measure of how widely actual results spread around the average.
Core formulas at a glance
- Probability of an event = favourable outcomes ÷ total outcomes.
- Probability an event does not occur = 1 minus the probability that it does.
- Probability of two dependent events in sequence = first probability × second probability given the first.
- Expected value = the sum, over outcomes, of probability × result.
Worked examples are in the article on probability formulas, and the sample figures above come straight from them.
Rounding and caution
Percentages on this page are rounded to one decimal place. Published odds tables for real games depend on the exact combination of rules, such as number of decks, dealer behaviour on soft 17 and which doubling and splitting options are allowed, so figures taken from an unrelated table may not match the game in front of you. Always read the rules posted at the table.
Gambling can be harmful. Set a limit you can afford before you start, and if play is causing you difficulty, contact a local support service.