GTO Charts Explained: How to Read and Use Preflop Range Charts

GTO preflop charts are the most practical tool in a tournament poker player’s study arsenal. Most players have heard the term but have never used a real chart set, relying instead on rough approximations or outdated ranges that cost them chips every session.

The Basics

A GTO chart is a visual representation of a game theory optimal preflop strategy for a specific position, stack depth, and tournament format. The output is a 13×13 matrix covering all 169 possible starting hand combinations. Each cell shows what action a GTO strategy takes with that hand: fold, call, raise, or go all-in. When a hand takes more than one action at equilibrium, the cell displays mixed colors showing the proportion of each.

GTO stands for game theory optimal. A GTO strategy is one that cannot be exploited by any opponent adjustment. If you deviate from it, a sufficiently skilled opponent can identify and punish that deviation for a profit. GTO charts are derived by running game tree solvers through millions of iterations until each player’s strategy converges on an equilibrium where neither side can improve by changing actions unilaterally.

A GTO chart is not a list of good hands. It is a precise, frequency-based strategy that accounts for the full structure of the situation: who is left to act, how likely each player is to call or 3-bet, what the pot geometry looks like at each stack depth, and how hands interact with postflop boards. A hand that is a clear open from the button may be a fold under the gun for these exact reasons.

If you are new to reading hand matrices, our Complete Beginner’s Guide to No-limit Hold’em training covers the foundational concepts before you work with chart data.

Position is Everything

Position is the most important variable in a preflop GTO chart, and the difference between positions is far larger than most players expect. At 50 big blinds in a multi-table tournament, our range data shows under the gun opening roughly 19% of hands. The button opens closer to 55%. That gap does not reflect tight versus loose tendencies. It reflects a fundamental structural difference in how each position interacts with the table.

Under the gun must act first with six or more players still to act behind.

Each player behind has a chance to 3-bet or flat call, and the UTG player will be out of position against most of the table for the rest of the hand.

These structural penalties require a tighter, stronger range to compensate. Only hands that perform well under those conditions earn a place in the UTG opening range.

The button faces a completely different situation. Only the small blind and big blind remain to act, and the button will be in position against both of them on every postflop street.

That positional advantage makes a broad range profitable. Hands that cannot sustain postflop pressure out of position become viable on the button because you can realize equity through continued aggression and well-timed folds with the best available information.

Stack Depth Is a Separate Variable

Stack depth is the second major variable in GTO preflop charts, and it compounds with position to produce a large matrix of distinct strategies. A correct chart set for tournament poker covers multiple stack depths, typically ranging from 10 or 15 big blinds through 100 big blinds, because the equilibrium strategy at 20 big blinds is materially different from the strategy at 50 big blinds.

At deeper stacks, players have more postflop streets to work with and considerably larger pots to contest. A hand’s value at depth depends on two related factors: its ability to realize equity across multiple streets, and its nut-making potential. Suited connectors and strong Broadway combinations gain value at depth precisely because they make the nuts. Hands that make second-best holdings are vulnerable to exactly the kind of large, multi-street pressure that deep stacks enable.

At shorter stacks, the postflop game is compressed or eliminated entirely. At 20 big blinds, many hands face a choice between open-jamming and folding, with only a narrow raise-small range available for hands strong enough to profit from it. Raw equity against calling ranges takes over as the primary driver. This is why A9 offsuit open-jams at 15 big blinds but would never jam at 40 big blinds, where a small raise is far more profitable.

Stack depth is particularly important in tournament poker, where your effective stack changes every level and every elimination. A chart set that covers only 50 to 100 big blinds leaves you without guidance for the 20 to 40 big blind range that represents a substantial portion of every tournament session.

How to Read a GTO Poker Chart: Colors and Mixed Strategies

A GTO chart uses color to encode action. The standard convention assigns a distinct color to each possible action: one color for fold, one for raise small, one for open-jam, and one for call or limp. The diagonal of the 13×13 matrix represents pocket pairs, the upper-right triangle represents suited hands, and the lower-left triangle represents offsuit hands. This layout lets you scan the chart and immediately identify which hand types are playable and from which section of the matrix opens are drawn.

Many hands in a GTO preflop chart show mixed colors rather than a single pure action. A cell that is half raise and half fold indicates that the hand takes each action at approximately equal frequency in the GTO strategy. This is not indecision or a chart error. Mixed strategies exist in equilibrium because a pure strategy on certain hands would be exploitable: if you folded a specific hand at 100% frequency, an observant opponent could adjust to take advantage of that pattern. Mixing keeps your ranges balanced and harder to counter.

At the table, you do not need to flip mental coins on mixed hands. The value of understanding mixed strategies is that they signal boundary hands. When a hand shows a mixed strategy in the chart, it sits very close to the profitability threshold for that action. Treating boundary hands as folds when uncertain is a lower-variance approach that costs very little in expectation.

Against tight or passive opposition, opening those boundary hands at full frequency becomes correct. When the players left to act fold too often, the fold equity on a raise increases and marginal hands become profitable opens. The clearest example is the button against a tight small blind and big blind pairing: if both players fold to steals at high rates, the button range widens beyond equilibrium. The reverse applies against loose or aggressive players who defend wide and 3-bet frequently. Boundary hands near the bottom of your opening range lose profitability when called too often, and the correct adjustment is to tighten.

The range matrix also makes the structure of a correct opening range visible at a glance. Strong ranges from early position are dominated by the top portion of the matrix: premium pairs, top Broadway suited combos, and the strongest offsuit Broadway hands. As you move to later position, the range expands through the suited connector section and down into the lower offsuit hands. This structural progression from top-left to bottom-right is a consistent feature of GTO preflop charts at all stack depths. If you are opening hands outside that structure or folding hands inside it, you have a leak.

When studying with GTO charts, start by learning the boundary hands at each depth rather than memorizing every cell. For a given position, identify the weakest hand that opens and the weakest hand that calls a 3-bet. Those boundaries define the shape of the range and are far easier to internalize than 169 individual decisions.

GTO Charts for ICM, PKO, and Tournament Formats

A chip EV preflop chart solves for the strategy that maximizes expected chips, treating each chip as equally valuable. Tournament poker does not work that way. Near the money bubble or a pay jump, chips you can lose are worth more than chips you can gain. This asymmetry, captured by the Independent Chip Model, means a chip EV chart is not the correct tool for ICM-relevant stages.

ICM-adjusted GTO charts account for this asymmetry by tightening ranges in spots where survival matters. A hand that is a profitable open at 30 big blinds in a chip EV model may become a fold at the same depth when ICM pressure is meaningful. Short stacks with fold equity operate somewhat differently: jamming ranges can widen relative to chip EV in certain configurations because the risk of busting is lower than the expected return from picking up the blinds and antes.

Progressive knockout formats introduce a separate variable. Bounty equity changes the value of getting all the chips in preflop, particularly when you cover an opponent whose bounty you would claim. This reshapes calling ranges and certain jamming ranges in ways specific to the bounty structure and stack depth relative to the target. A chart set designed for standard MTTs does not produce correct strategy for PKO play.

A chip EV preflop chart is the correct starting point for most tournament hands, but ICM-adjusted charts are required near the bubble and at the final table. Using chip EV charts in those situations will consistently lead to calling too wide and jamming too tight. Both errors compound over a tournament series.

The Most Common Mistakes When Applying Chart-Based Ranges

The most widespread mistake is applying a single range to multiple positions. Many players learn one opening range, perhaps 20 to 25%, and use it from every position. A GTO preflop chart reveals how costly this is: the UTG range and the cutoff range at the same stack depth share many hands, but the hands unique to the cutoff range are precisely those that need positional advantage to be profitable. Playing them from early position bleeds chips in small increments that compound over a session.

A related mistake is ignoring stack depth and applying a 100 big blind chart to 25 big blind situations. At shorter stacks, the correct strategy often involves open-jamming hands that a deep-stack chart would raise small. Raising small with those hands at short stacks creates awkward pot sizes and stack-to-pot ratios that are difficult to navigate postflop.

A third mistake is treating GTO charts as a ceiling rather than a foundation. GTO strategy represents the unexploitable baseline. Against opponents who deviate predictably from equilibrium, exploitative adjustments improve your results. A player who folds too much to continuation bets warrants more frequent c-bets. A player who calls opening raises with very weak hands warrants a tighter value range and fewer bluffs. The chart tells you where equilibrium is. Your read on the table tells you which direction to deviate from it.

Finally, many players study charts without accounting for 3-bet dynamics. A chart showing your opening range assumes opponents 3-bet at roughly equilibrium frequencies. Against players who 3-bet far more aggressively, hands near the bottom of your opening range become folds because the reduced fold equity makes the open unprofitable. Against players who almost never 3-bet, you can open wider and realize more equity from hands that would otherwise be borderline.

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