Blackjack is known for having one of the lowest house edges in the casino. With proper strategy, the house edge can be as low as 0.5%. But what does that actually mean? And why do casinos still profit if the edge is so small? Understanding house edge helps you set realistic expectations, choose better games, and recognize when rules significantly change your odds. It also clarifies why blackjack can't be beaten long-term without card counting. This guide explains what house edge is, how it's calculated, what factors affect it, and what a 0.5% edge means in practice. We'll also cover why small rule changes can make a big difference to your bottom line.
What Is House Edge?
House edge is the mathematical advantage the casino has over players, expressed as a percentage. It represents the average amount of each bet the casino expects to keep over the long term.
Example:A game with a 0.5% house edge means the casino expects to keep $0.50 for every $100 wagered over thousands of hands.
Important clarifications:- House edge is a long-term average across thousands or millions of hands - It doesn't predict what will happen in a single session - You can win or lose any individual session regardless of the house edge - Over time, the house edge ensures the casino profits In blackjack, the house edge is relatively low compared to other casino games, which typically range from 1% (baccarat, craps) to 5-15% (roulette, Caribbean stud poker).
Why Blackjack Has a Low House Edge
Blackjack's house edge is low for several reasons:
1. Player decisions matterUnlike slots or roulette, your choices directly affect outcomes. Optimal strategy minimizes the house's advantage.
2. Natural blackjack pays moreWhen you get a natural blackjack (Ace plus 10-value card on the first two cards), you're paid 3:2 on most tables. The dealer's natural only ties your natural, not pays extra.
3. You can double and splitThese options let you increase your bet in favorable situations, which reduces the house edge.
4. You can see one dealer cardThe dealer's upcard gives you information to make better decisions. However, the dealer still has one critical advantage:
they play last. If you bust, you lose immediately, even if the dealer later busts too. This single rule is where the house edge comes from.
How House Edge Is Calculated
House edge is calculated by simulating millions of hands and comparing total bets to total returns.
For blackjack with perfect basic strategy and standard rules:- House edge: approximately 0.5%
For players who don't use basic strategy:- House edge: 2-4% or higher The exact percentage depends on: - The specific table rules - How well you play - Number of decks used - Whether the dealer hits or stands on soft 17 - Blackjack payout (3:2 vs 6:5) For more on optimal playing decisions, see our [blackjack strategy guide](#).
Rule Variations and Their Impact
Small rule changes significantly affect the house edge. Here's how common variations impact your odds:
Blackjack Payout: 3:2 vs 6:5
Standard (3:2): A $10 bet wins $15 on blackjack
Inferior (6:5): A $10 bet wins $12 on blackjack
Impact: Moving from 3:2 to 6:5 increases the house edge by approximately
1.4%. This single rule change is one of the worst you can encounter. Always avoid 6:5 blackjack tables.
Dealer Hits or Stands on Soft 17
Dealer stands on soft 17: Standard and player-friendly
Dealer hits on soft 17: Gives the dealer more chances to improve weak hands
Impact: Dealer hitting soft 17 increases the house edge by approximately
0.2%.
Number of Decks
Single deck: Lowest house edge
Double deck: Slightly higher
Six or eight decks: Standard in most casinos
Impact: Moving from single-deck to eight-deck increases the house edge by approximately
0.5%. Single-deck games are rare because they give skilled players (especially card counters) better odds.
Doubling Rules
Can double on any two cards: Player-friendly
Can only double on 10 or 11: Restrictive and increases house edge
Impact: Restricting doubling increases the house edge by approximately
0.2-0.3%.
Surrender Option
Late surrender available: Slightly player-friendly
No surrender: Standard
Impact: Late surrender reduces the house edge by approximately
0.05-0.1%.
Re-Splitting Aces
Allowed: Slightly player-friendly
Not allowed: Standard
Impact: Minor, approximately
0.05% reduction when allowed.
What a 0.5% House Edge Means in Practice
Let's break down what a 0.5% house edge looks like in real money:
Example 1: 100 hands at $10 per hand- Total wagered: $1,000 - Expected loss (0.5% edge): $5
Example 2: 1,000 hands at $10 per hand- Total wagered: $10,000 - Expected loss (0.5% edge): $50
Important notes:- These are long-term averages - Actual results in any session will vary significantly - You could win or lose much more in the short term - Variance (luck) dominates short-term results A 0.5% edge means blackjack is one of the lowest-cost casino games from a mathematical perspective. But "low cost" doesn't mean "no cost" — over time, the edge ensures the casino profits.
House Edge vs Variance
House edge is different from variance (also called volatility).
House edge: The long-term mathematical advantage the casino has
Variance: The short-term swings — how much you can win or lose in a session Blackjack has moderate variance. You can have winning or losing streaks that feel much larger than the 0.5% edge would suggest. This is normal and expected.
Example:You might play 100 hands and win $200, or lose $150. Neither outcome contradicts the 0.5% house edge, because variance creates these swings in the short term. For more on how variance works, see our guide on [RTP and volatility](#).
Can You Overcome the House Edge?
For most players, no. The house edge is built into the game structure.
The only proven way to overcome the house edge is card counting:- Requires tracking which cards have been played - Requires perfect basic strategy - Requires significant bankroll and discipline - Is legal but often prohibited by casinos (they can refuse service) - Doesn't work in online blackjack (decks are shuffled after every hand) Card counting doesn't guarantee wins — it reduces the house edge to slightly negative (around -0.5% to -1% in the player's favor) in ideal conditions. Even professional card counters experience losing sessions.
For players not counting cards:- The house maintains a 0.5% edge with perfect basic strategy - The edge increases to 2-4% with poor strategy - There's no system, pattern, or betting strategy that eliminates the edge
Comparing Blackjack to Other Casino Games
Blackjack's 0.5% house edge (with basic strategy) makes it one of the best bets in the casino.
Typical house edges:- Blackjack (basic strategy): 0.5% - Baccarat (Banker bet): 1.06% - Craps (Pass/Don't Pass): 1.4% - European Roulette: 2.7% - American Roulette: 5.26% - Caribbean Stud Poker: 5.22% - Slots: 2-15% (varies widely) - Keno: 20-40% From a pure math perspective, blackjack and baccarat offer the best odds. But that doesn't mean you should only play these games — personal preference and entertainment value matter too.
Why Casinos Still Profit
If the house edge is only 0.5%, how do casinos make money on blackjack?
1. Most players don't use basic strategyThe average player has a house edge against them of 2-4%, not 0.5%.
2. Volume of playCasinos deal thousands of hands per day. Small edges add up over massive volume.
3. Side betsMany blackjack tables offer side bets (like "Perfect Pairs") with house edges of 5-10% or more. These generate significant revenue.
4. Table minimums and maximumsBet limits prevent players from using certain betting systems and protect the casino from rare extreme outcomes.