Blackjack Basic Strategy Chart: How to Read and Use It
A basic strategy chart is a complete decision table: for every combination of your hand and the dealer's upcard, it tells you the single mathematically optimal play. Using it correctly reduces the house edge to under 0.5%.
The 340-cell chart at 21simulator.com links every decision to its expected value — click any cell to see the math.
What the Chart Contains
A full basic strategy chart covers three hand categories, each representing a section of the table:
- Hard totals: Hands without an ace, or where the ace counts as 1. Totals from 5 through 21 against dealer upcards 2–Ace. This is the largest section and covers the majority of hands you'll play.
- Soft totals: Hands with an ace counted as 11. Soft 13 (A-2) through soft 20 (A-9) against dealer upcards 2–Ace. Soft hands are played more aggressively because the ace can revert to 1 if you bust.
- Pairs: Identical first-two-card combinations (2-2 through A-A) against dealer upcards 2–Ace. Split decisions depend heavily on whether the game offers double after split (DAS).
The interactive chart at learn.21simulator.com/strategy/chart covers all 340 situations for a standard 6-deck, H17, DAS game and links each cell to a detailed explanation with EV comparisons.
Chart Abbreviations Decoded
Printed strategy charts use abbreviations to fit all 340 decisions into a compact table. Every code you'll encounter:
| Code | Meaning | When Applied |
|---|---|---|
| H | Hit | Draw another card |
| S | Stand | Take no more cards |
| D | Double | Double bet, take exactly one more card |
| P | Split | Separate pair into two hands |
| R | Surrender | Forfeit half the bet, fold the hand |
| Dh | Double if allowed, else Hit | Double when game permits; otherwise hit |
| Ds | Double if allowed, else Stand | Double when game permits; otherwise stand |
| Ph | Split if DAS allowed, else Hit | Split when double-after-split is available; otherwise hit |
| Rh | Surrender if available, else Hit | Surrender when late surrender is offered; otherwise hit |
| Rs | Surrender if available, else Stand | Surrender when late surrender is offered; otherwise stand |
Conditional codes (Dh, Ds, Ph, Rh, Rs) reflect that some actions aren't available in all games. Always play the primary action when the condition is met; fall back to the secondary when it isn't.
How to Look Up a Hand
Using a chart at the table:
- Determine your hand type: is it a pair? A soft hand? A hard total?
- Find the correct section of the chart (pairs, soft, or hard).
- Find your hand total (or specific pair) in the left column.
- Find the dealer's upcard in the top row.
- The cell where they intersect is your action.
A few hands require disambiguation:
- A-7 (soft 18): Look up in the soft section, not as hard 8.
- 5-5 (pair of 5s): Do not look up in pairs — look up as hard 10 in the hard section. Never split 5s.
- A-A (pair of aces): Always in the pairs section. Always split.
- Hand with 3+ cards: Use the total as a hard or soft total. Multi-card hands are still looked up by total — the chart doesn't care how many cards you hold.
A Memorization Framework
The chart has roughly 270 distinct cells, but most reduce to a small set of learnable rules. Work through these stages rather than trying to memorize every cell individually:
Step 1: Hard totals (the most common situation)
- 8 or less: always hit.
- 9: double vs dealer 3–6; hit otherwise.
- 10: double vs 2–9; hit vs 10 or Ace.
- 11: double vs 2–10 (S17) or 2–Ace (H17).
- 12: stand vs 4–6; hit otherwise.
- 13–16: stand vs 2–6; hit vs 7–Ace. (Surrender 15 vs 10; 16 vs 9, 10, Ace if available.)
- 17+: always stand.
Step 2: Pair absolutes (lock these in first)
- Always split Aces and 8s.
- Never split 5s or 10s.
- Remaining pairs: conditional (see chart).
Step 3: Soft totals
- Soft 13–16 (A-2 through A-5): double vs 4–6 (A-4, A-5) or 5–6 (A-2, A-3); hit otherwise.
- Soft 17 (A-6): double vs 3–6; hit otherwise. Never stand.
- Soft 18 (A-7): double vs 3–6; stand vs 2, 7, 8; hit vs 9, 10, Ace.
- Soft 19–20: always stand.
Which Chart to Use
Strategy charts are rule-dependent. The chart for 6-deck H17 differs from single-deck S17 in roughly a dozen situations. Using the wrong chart introduces small but real EV errors. Match your chart to your game:
- 6-deck, H17 (most Strip games): Standard published charts typically cover this. Double hard 11 vs Ace; surrender hard 15 and 17 vs Ace.
- 6-deck, S17 (off-Strip, downtown): Hit hard 11 vs Ace instead of doubling; remove hard 15 and 17 vs Ace surrenders.
- Single-deck, S17: Several additional differences — hard 8 doubles vs 5–6, soft hand windows change. Use a dedicated single-deck chart.
The interactive chart on this site is configured for 6-deck H17 — the rule set you'll encounter most often in modern U.S. casinos.
Using a Chart at the Table: Is It Allowed?
Yes, in most casinos. Printed basic strategy cards are sold openly in casino gift shops. Using one at the table is legal and accepted — the house edge is sufficient that casinos profit from your optimal play. Some dealers may ask you to keep it off the felt; holding it in your hand is always acceptable.
The goal is to internalize the chart well enough that you don't need it under time pressure. Card access is a training wheel — use it, but plan to remove it once the decisions become automatic.