ganak.appBlackjack Calculator
Free blackjack calculator with 3 modes: get optimal strategy advice for any hand, view the full basic strategy chart, and calculate house edge for your game rules. Shows expected value for every action.
Select your two cards and the dealer's upcard to see the optimal play
Understanding Blackjack Basic Strategy
What basic strategy is and why every player should use it
Basic strategy is the mathematically optimal way to play every possible blackjack hand. It was first computed in the 1950s by Roger Baldwin and later perfected by Edward Thorp using computer simulations of millions of hands. When you follow basic strategy perfectly, you reduce the house edge to as low as 0.26% — making blackjack one of the best odds in any casino.
How basic strategy works
Basic strategy considers two pieces of information: your hand total (and whether it's hard or soft) and the dealer's face-up card. For every combination, mathematics tells us which action — Hit, Stand, Double Down, Split, or Surrender — gives the highest expected value. This calculator uses those derived tables, adjusted for your specific game rules.
Hard Totals, Soft Totals & Pairs
The three categories that determine your optimal play
Hard Totals
A hand without an Ace counting as 11. Hard hands have a real risk of busting when hitting. You stand more often against weak dealer cards (2-6) and hit more against strong ones (7-A).
Soft Totals
A hand containing an Ace counted as 11. Soft hands are flexible — the Ace can revert to 1, so you can never bust on one hit. This makes doubling down more attractive against weak dealer cards.
Pairs
When your two cards have equal value, you can split them into two separate hands. Always split Aces and 8s. Never split 10s or 5s. Other pairs depend on the dealer’s upcard and DAS rules.
How House Edge Works in Blackjack
Understanding the casino's mathematical advantage
The house edge is the percentage of each bet the casino expects to keep over the long run. In blackjack, the house edge depends entirely on the rules of the specific table you're playing at. With optimal basic strategy and favorable rules, the edge can be as low as 0.26%. With poor rules (like 6:5 payouts), it can exceed 2%.
The biggest factor is the blackjack payout. Tables paying 6:5 instead of 3:2 add a massive 1.39% to the house edge — roughly six times worse. Always check the payout before sitting down.
Common Blackjack Mistakes to Avoid
Costly errors that increase the house edge
Taking insurance
Insurance is a sucker bet. It pays 2:1 but the odds of the dealer having blackjack are less than 1 in 3. Basic strategy says never take insurance — it costs about 7% on the side bet.
Standing on soft 17
With a soft 17 (A+6), you should always hit or double against dealer 3-6. You can't bust a soft hand on one hit, and 17 loses more often than it wins.
Splitting 10s
A total of 20 is the second-best hand in blackjack. Splitting 10s gives you two weaker hands starting from 10 — always stand on 20.
Not splitting 8s vs a 10
Hard 16 is the worst hand in blackjack. Splitting 8s gives you two chances to improve. Even against a dealer 10, splitting is less costly.
Playing 6:5 tables
The 6:5 payout adds 1.39% to the house edge — roughly six times worse than a standard 3:2 table. Always look for 3:2 tables.
Frequently Asked Questions
Common questions about blackjack strategy, odds, and optimal play