Strategy Guide

From the rules of the table to the chart this app teaches — one short page.

0. How the game works

Goal: get a hand total closer to 21 than the dealer, without going over (busting).

Card values: 2–9 are face value, 10/J/Q/K all count as 10, and an Ace counts as 1 or 11 — whichever doesn't bust. A hand that uses an Ace as 11 is called a soft hand (e.g. A,6 = soft 17).

The deal: you get two cards face up, the dealer gets one face up (the upcard) and one face down (the hole card). You play your hand to completion, then the dealer reveals and plays theirs.

Your moves:

• Hit — take another card.
• Stand — keep your total, end your turn.
• Double — double your bet, take exactly one more card, then stand. First decision only.
• Split — if your two cards have the same value, split into two hands (each gets a new card) and play them independently. Costs a second bet.
• Surrender — fold the hand and get half your bet back. First decision only (late surrender, this variant).

Payouts:

• Beat the dealer → +1 unit per unit bet.
• Lose, or bust at any point → −1.
• Same total → push (0).
• Blackjack (Ace + 10-value on the deal) → +1.5. If the dealer also has blackjack, push.

Dealer strategy

That fixed rule is the whole game's pivot. The dealer must draw on stiff hands (12–16) and so will bust often when their upcard is weak (2–6). They can't punish you when they're vulnerable. Your edge — the only edge a player ever gets — comes from making smarter choices than they're allowed to.

Dealer bust rate by upcard

Here's how often the dealer ends up busting, just from following that rule. The split between 6 and 7 is the most important number in blackjack:

Computed exactly by this app's solver (js/solver.js): infinite-deck S17, conditioned on the dealer not having a natural blackjack (matches what the player actually sees once the hand starts). Bars scaled linearly (max ≈ 42%).

Two things to read off this:

• 2–6 are "bust cards" — the dealer busts roughly 35–43% of the time. Stand on anything 12+ and let them break their own hand.
• 7–A are "strong cards" — the dealer ends up at 17+ four times out of five. Sitting on a stiff 13 against a 10 just hands them the hand; you have to draw and risk busting yourself.

1. The simplest strategy: mimic the dealer

The most natural-looking strategy is to copy the dealer's rule yourself: hit on anything below 17, stand on 17+, never double, split, or surrender.

It feels safe. It is, in fact, the worst common strategy:

Roughly 5.5 units lost per 100 hands. Three reasons make it that bad:

• You bust first. If you both bust, you've already lost — the dealer never has to draw. By copying their rule, you take on all the bust risk and get none of the "they bust, I sit on 13" upside.
• No 3:2 blackjack bonus. The dealer doesn't get paid 1.5× on a natural — you would, and you're throwing it away by not playing differently from them.
• No doubling, no splitting. You never push extra money in on hands where you have the edge (hard 11, pair of 8s, A,A).

For reference, with this variant the optimal basic strategy gives the house only about 0.5% — roughly ten times less. The next section walks from the 5.5% baseline down to that number in three steps.

2. Improving step by step

You don't need to memorize the whole chart at once. Each of the levels below shaves a chunk off the 5.5% baseline.

2A. Hard totals

One rule of thumb already eliminates most of the leak:

A few specifics refine it (12 vs 2–3 is actually hit; 11 vs Ace is hit), but ignoring them costs almost nothing. With this alone you're already close to:

That's more than half the edge gone, just from knowing when to stop drawing.

Soft hands (any hand with an Ace counted as 11) need their own short rule because the Ace makes you bust-proof on one more card:

2B. Doubles

Doubling means: commit a second unit, take one card, stand. It's worth it when one extra card is very likely to land you on a strong hand against a weak dealer.

The doubles that matter most, in order of frequency × value:

• Hard 11 vs almost any dealer upcard — your most common doubling spot.
• Hard 10 vs dealer 2–9 — same logic, slightly weaker.
• Hard 9 vs dealer 3–6 — only when the dealer is weakest.
• Soft doubles — the higher your soft total, the more upcards qualify: A,6–A,7 vs 3–6; A,5 vs 4–6; A,3–A,4 vs 5–6; A,2 vs 6 only. The Ace gives you a safety net if the extra card is small.

2C. Splits

Only three things to memorize:

• Always split A,A and 8,8 — vs every upcard. Two aces are worth far more apart than as a soft 12; two 8s start at a miserable 16, splitting gives you two chances at a real hand.
• Never split 5,5 or 10,10 — a pair of fives is just a hard 10 (double-down material); a pair of tens is a 20 (already great, don't break it).
• For the other pairs, split when the dealer is weak (roughly 2–6/7), hit otherwise. The chart fills in the details.

2D. Surrenders

Three cells, that's it — give up the hand for half your bet back instead of playing it out:

• Hard 16 vs dealer 9, 10, or A.
• Hard 15 vs dealer 10.

You'll lose those hands roughly 60% of the time. Taking the half-unit refund beats playing them out.

2E. Adjustments

The narrow exceptions where both mimic and the bust-card rule are wrong. Under S17 there are essentially only three cells:

• Soft 18 (A,7) vs dealer 9, 10, or A — hit, don't stand. Both rules say "stand on 18+", but the dealer's strong card wins ≥ 60% of the time against your 18, and one more card can't bust you anyway.

Tiny bucket, tiny EV — but if you've automated everything else, this is what's left.

Using this app

In Practice mode you get random situations and immediate feedback per decision. The badge next to each hand label tells you whether the action is the same regardless of dealer upcard — ✓ means fixed (memorize it once), ? means upcard-dependent (the harder cells).

In Play mode you play full hands against a real dealer and a 6-deck shoe. Every move is still scored against the chart, and the result banner counts how many misplays the hand contained.