What the 13×13 grid is
Every preflop chart is the same shape: a 13×13 grid of the 169 distinct starting hands. The diagonal is the pocket pairs, running AA down to 22. Everything above the diagonal is suited (AKs, QJs), everything below it is offsuit (AKo, QJo). Suited hands sit above because that is the convention, and it is worth knowing which half you are looking at before you act on it.
The 169 cells are not equally likely. A pocket pair is 6 combinations, a suited hand 4, an offsuit hand 12. So the offsuit half of the grid, which looks like half the chart, is actually the bulk of your range — which is why a chart that folds most of the offsuit region is much tighter than it looks.
| Hand type | Cells in the grid | Combinations each | Share of all 1,326 hands |
|---|---|---|---|
| Pocket pair | 13 | 6 | 5.9% |
| Suited | 78 | 4 | 23.5% |
| Offsuit | 78 | 12 | 70.6% |
Why a cell is 40% red: mixed strategies
The single most misread feature of a solved chart is the partially-coloured cell. A chart that shows A5s as 62% raise and 38% call is not saying the solver is unsure. It is saying that the equilibrium strategy raises that hand 62% of the time and calls with it 38% of the time, and that both numbers are load-bearing.
They are load-bearing because the alternative is exploitable. If you always raise A5s and always call A6s, an observant opponent learns that your calling range never contains a wheel ace, and can attack every board that brings one. Mixing is how a range stays unreadable — the same reason a solver produces odd-looking bluffs.
A mixed cell is an instruction, not a hedge. 62% raise means raise this hand roughly six times out of ten, decided by something your opponent cannot see — the suits, the second hand of a clock, anything arbitrary.
In practice almost nobody randomises properly at the table, and it costs less than you would think. The EV difference between a 62/38 mix and always raising is usually a fraction of a big blind per hundred hands. What is expensive is picking the *wrong* pure action — always folding a hand the chart raises 62% of the time is a real error, always raising it is nearly free.
How position changes everything
Position is the largest single input to a preflop range, larger than stack depth and far larger than anything about your opponents. The reason is mechanical: acting last postflop is worth a great deal of expected value, and hands that are marginal out of position become clearly profitable in position.
Opening ranges therefore widen monotonically as you approach the button. The exact figures depend on table size and depth, but the shape is stable:
| Position | Approximate open % | What gets added |
|---|---|---|
| UTG | 15–18% | Premiums, strong broadways, the better suited connectors. |
| Hijack | 20–24% | Weaker suited aces, more suited connectors, small pairs. |
| Cutoff | 26–30% | Most suited hands, offsuit broadways. |
| Button | 42–50% | Nearly every suited hand and a wide offsuit range — position is worth that much. |
| Small blind | 35–45% | Wide, but this is a raise-or-fold spot out of position with a very different postflop life. |
The button number surprises people every time. It is correct, and it is the most reliable source of expected value available to a player who is not yet good postflop: the button is the seat where a chart alone earns money. The free chart shelf will show you the exact range for any position, table size and stack depth without an account.
Stack depth, and why tournament charts look wrong
Preflop ranges are a function of the effective stack, and the relationship is not a smooth widening or tightening — it changes shape.
Deep (100bb and up)
Implied odds matter. Suited connectors and small pairs gain value because the times they hit, they win a large stack. Offsuit broadways lose relative value: they make top pair with a weak kicker, which is exactly the hand that loses a big pot deep.
Mid (40–60bb)
The reverse. There is no longer enough money behind to pay off a set, so small pairs and speculative suited hands shed value, while hands with raw high-card strength gain it. This is the depth most tournament play actually happens at, and applying a 100bb cash chart here is a common and expensive mistake.
Short (under 25bb)
Postflop play largely disappears and the game becomes push/fold or raise/call-a-jam. Ranges become almost purely about equity when called, which is why short-stack charts contain hands like K5o that a deep-stacked chart never opens. See push/fold charts for how those are derived.
The half of the chart people skip: defending
Most players learn opening ranges and stop. Opening is roughly a fifth of the preflop decisions you make; the rest are responses — defending the big blind, flatting in position, 3-betting, and facing a 3-bet. Those are where the money is lost.
- Big blind defence is the widest range in poker, and the one people underplay most. You are getting a discount — part of your bet is already in — and closing the action. Against a button open at 2.5x you are defending something close to half your hands.
- 3-betting is built from two groups, not one: value hands strong enough to want a bigger pot, and hands just below the calling threshold that play better as a raise than a call. The gap between them is deliberate — it keeps the range balanced.
- Facing a 3-bet is where charts get tightest and errors get largest. Continuing too wide out of position against a 3-bet is one of the most consistently expensive leaks in the game.
- Cold-calling ranges are narrower than people expect, because a caller can be squeezed by everyone still to act.
If you have limited study time, the ordering that returns the most is: big blind defence, then facing a 3-bet, then opening, then everything else.
Getting a chart out of the PDF and into your play
Reading charts does not transfer to playing them. This is the part everybody knows and nobody acts on, so it is worth being blunt: staring at a grid produces recognition, and at a table you need recall under time pressure, which is a different mental operation trained by a different activity.
- Learn the boundaries, not the cells. A range is defined by where it stops — which suited ace, which offsuit broadway, how far down the pairs. Four or five boundaries per position is the whole chart.
- Learn one position at a time, and start with the button and the big blind, which cover the most hands.
- Treat every mixed cell as its majority action at first. The randomisation is worth a fraction of a big blind; the boundary is worth several.
- Then test yourself under time pressure, which is the only step that builds recall. Being dealt the spot and having to act is what makes the boundary stick.
That last step is what the first chapters of the bootcamp do — the trainer deals the spot, you act, and the solved range prices your decision in big blinds before the next hand. Chapter one needs no account and no card. If you want to check a range while you play instead, the chart shelf is free and covers every game type, table size, depth and seat.
Frequently asked questions
How do you read a GTO preflop chart?
The 13×13 grid holds all 169 starting hands: pocket pairs on the diagonal, suited hands above it, offsuit below. Each cell’s colour shows the action, and a partially coloured cell is a mixed strategy — a cell shown as 62% raise means the equilibrium raises that hand about six times in ten and takes the other action the rest of the time.
Why does a solver raise the same hand only some of the time?
Because always taking one action with a given hand makes the range readable. If you always raise A5s and always call A6s, an opponent learns your calling range contains no wheel aces and can attack every board with one. Mixing keeps the range balanced, which is the entire purpose of a game-theory-optimal strategy.
Do preflop charts change with stack depth?
Substantially, and they change shape rather than just width. Deep stacks favour suited connectors and small pairs because implied odds are large. Around 40–60bb those hands lose value and raw high-card strength gains it. Below about 25bb the game becomes push/fold and ranges are driven almost purely by equity when called.
What is the widest opening range in poker?
The button, at roughly 42–50% of hands in a 6-max game at 100bb — nearly every suited hand plus a wide offsuit range. Acting last on every postflop street is worth enough expected value to make hands profitable there that are clear folds from any earlier seat.
Are free preflop charts good enough?
Yes, for essentially everyone. Preflop solutions are stable and well understood, and the difference between a good free chart and an expensive one is far smaller than the difference between knowing a chart and recalling it under time pressure at a table. GTO Academy’s chart shelf is free for every game type, table size, stack depth and seat, with no account.