Why the same game can be a good bet or a bad one
Two blackjack tables can look identical from across the pit — same felt color, same $10 minimum, same dealer smile — and have a house edge that differs by more than 1.5 percentage points. That gap comes entirely from five rules printed in small text on the felt: deck count, whether the dealer hits or stands on soft 17, double after split, surrender availability, and the blackjack payout ratio. Casinos know most players never check. This tool exists so you can, in about ten seconds, before you sit down.
Comment fonctionne ce calculateur — Formulas & Method
Source: published composite of Wizard of Odds / Blackjack Apprenticeship rule-effect tables · Deterministic arithmetic — no AI, no estimation
Constants used
| Rule | Effect on house edge | Baseline |
|---|---|---|
| 1 deck | −0.48 pp | vs 6-deck baseline |
| 2 decks | −0.35 pp | vs 6-deck baseline |
| 4 decks | −0.06 pp | vs 6-deck baseline |
| 6 decks | 0 pp (baseline) | — |
| 8 decks | +0.01 pp | vs 6-deck baseline |
| Dealer hits soft 17 (H17) | +0.22 pp | vs S17 |
| No double after split | +0.14 pp | vs DAS allowed |
| Late surrender allowed | −0.08 pp | vs no surrender |
| 6:5 blackjack payout | +1.39 pp | vs 3:2 |
Formula
baseline = 0.46// 6-deck, S17, DAS, no surrender, 3:2
edge = baseline
+ deck_count_delta
+ (h17 ? 0.22 : 0)
+ (no_das ? 0.14 : 0)
− (surrender ? 0.08 : 0)
+ (payout_6_5 ? 1.39 : 0)
Deterministic composition of published per-rule deltas. Real-world edges can shift slightly with penetration and exact resplit/re-double rules not modeled here — treat this as a fast screening estimate, not a certified figure.
What each rule actually costs you
| Rule change | Cost per $100 wagered |
|---|---|
| 6:5 instead of 3:2 payout | $1.39 |
| Dealer hits soft 17 instead of stands | $0.22 |
| No double after split | $0.14 |
| 6 decks instead of 1 deck | $0.48 |
| No late surrender | $0.08 |
This tool gives a fast screening estimate for one rule combination at a time. But most casinos run 3-5 different blackjack tables simultaneously with different rule sets — and the only way to actually play any of them correctly is to know the right move for every hand under that table's exact rules, not just its overall edge.
That's what a full rule-set-aware house edge calculator is for — same underlying logic as this quick check, but paired with a live basic-strategy engine so you get both numbers at once:
- Before you sit down: plug in the felt's exact rules on the house edge calculator to confirm it's worth playing.
- While you're deciding a hand: the blackjack calculator gives the mathematically optimal hit/stand/split/double/surrender call for your exact cards and that table's rules.
- To memorize the whole strategy for a rule set: the basic strategy chart generates dynamically per rule set instead of forcing you to approximate from a generic printed card.
- To test a bankroll or session length before risking real money: the blackjack simulator runs thousands of hands under your chosen rules and shows your realized edge versus the theoretical one.
- To check exact payouts on a hand: the payout calculator handles 3:2, 6:5, insurance, and bet-size math instantly.
Every calculator on the site is free, requires no signup, and runs on deterministic table-driven math — checked cell-for-cell against published basic-strategy references, not an AI guess.
Try the full Blackjack Calculator →Frequently asked questions
What is the house edge in blackjack?
The casino's long-run statistical advantage, expressed as a percentage of every dollar wagered, assuming perfect basic strategy. Standard 6-deck, S17 tables run about 0.46%; the exact number moves with every rule variation.
Does deck count really change the house edge?
Yes. Fewer decks favor the player — a single-deck game with otherwise standard rules cuts the house edge by roughly 0.48 percentage points versus a 6-deck shoe.
Why does 6:5 blackjack pay so much worse than 3:2?
3:2 pays $15 profit on a $10 blackjack; 6:5 pays only $12. That gap alone adds roughly 1.4 percentage points to the house edge.
Is dealer hits soft 17 (H17) worse for the player?
Yes, roughly +0.22 percentage points versus a dealer who stands on soft 17 (S17) — more chances for the dealer to improve a weak hand.
Does surrender lower the house edge?
Late surrender, used correctly, lowers the house edge by roughly 0.08 percentage points by letting you forfeit half your bet on the worst starting hands instead of playing them out.
What's the single best rule to look for at a blackjack table?
Avoid 6:5 blackjack payout above everything else — it costs roughly 3x more than any other single rule change. After that: fewer decks, S17, and double after split allowed.