Tools
Blackjack Calculator
See the math behind every blackjack decision. Enter your hand, the dealer’s up-card, and the table rules.
We run thousands of simulations and show the expected value of every legal action, plus the probability you win, push, or lose.
Looking for “what should I play?” This calculator goes deep on EV math. If you just want a clean answer for any hand, use our free simulator (with hint mode) or look up our interactive strategy chart.
Your hand
How does the calculator work?
The math behind blackjack has no clean closed-form answer. Every credible blackjack tool either uses a precomputed table from Wizard of Odds, or runs a Monte Carlo simulation.
We run a Monte Carlo. For each legal action (Hit, Stand, Double, Split, Surrender), we simulate thousands of fresh shoes, deal them out, follow basic strategy after the initial action, and average the result.
More iterations means more precision. 10,000 iterations gives a standard error around 0.5% on the expected value. 25,000 cuts that to about 0.3%.
What is expected value (EV)?
Expected value is what you win or lose on average per dollar bet, played out over thousands of hands.
+0.05 means every dollar bet returns 5 cents on average. Long term, you win.
-0.05 means every dollar bet loses 5 cents on average. Long term, you lose.
0.00 is break-even. You win as much as you lose.
The action with the highest EV is mathematically the best play. Sometimes the best play still has a negative EV. That just means the situation is bad, and any other action would be even worse.
Why does the EV change with the rules?
Every rule shifts the math. Switching the dealer rule from S17 to H17 adds about 0.22% to the house edge across the board.
6:5 blackjack payouts are the worst rule on any table. They add 1.4% to the house edge for almost no upside.
Late surrender, allowed doubling after split, and re-splittable aces all shift the edge in the player’s favor.
When you change the rules in the calculator, the EV per action recomputes against the new shoe and dealer policy.
Practice the math live
Once you understand the EV behind a decision, drill it. Open the free blackjack simulator and play through hands with the hint mode on.
For the lookup version, the interactive basic strategy chart shows every cell of the chart with the same math we use here.