How to Read a Preflop Range Chart (the 13×13 Grid Explained)

June 29, 2026 · GTO Lab

The 13×13 grid is everywhere in poker study: in solver outputs, coaching videos, and strategy articles. It is compact, information-dense, and — once you know how to read it — surprisingly intuitive. This guide walks through everything you need to decode a preflop range chart, from the basic anatomy to what the colors and frequencies actually mean.

The Anatomy of the Grid

The grid represents all 169 distinct starting hand combinations in Texas Hold’em. Every possible two-card hand maps to exactly one cell.

Here is how the grid is organized:

The diagonal (top-left to bottom-right) contains pocket pairs: AA in the top-left corner, then KK, QQ, JJ… down to 22 in the bottom-right corner.
Above the diagonal are suited hands. AKs sits in the cell where the Ace column meets the King row. Each suited hand is just four combinations, each pocket pair is six, and each offsuit hand is twelve — so offsuit hands carry the most combinations and suited hands the fewest.
Below the diagonal are offsuit hands. AKo, for example, sits just below AKs in the grid.

The convention is consistent across all solvers: the higher card indexes the column, the lower card indexes the row, pairs on the diagonal, suited above, offsuit below. Once you have seen it a few times it becomes automatic.

What the Colors Tell You

Range charts use color to show which action the solver recommends for each hand. The specific colors vary by tool, but the logic is always the same:

Solid color — the solver uses this action for that hand 100% of the time.
Split or mixed color — the solver recommends mixing between two or more actions.

Typical color conventions you will see:

Color	Action
Green	Raise / open-raise
Blue	Call
Red / gray	Fold
Yellow	Sometimes raise, sometimes call

A cell that is half green and half blue means the solver raises that hand 50% of the time and calls the other 50%. This is a mixed strategy — the deliberate randomization that makes a balanced range unexploitable.

Mixed Strategies: Why They Exist

Mixed strategies are the part of range charts that confuse most beginners. Why would you ever do different things with the same hand?

The answer comes from game theory. If you always raise pocket nines from the cutoff, a smart opponent can put you on a range that excludes 99 when you do anything else. You become predictable. By mixing — say, raising 99 70% of the time and calling 30% — you maintain nines in multiple lines, making your overall range harder to read.

You do not need to count frequencies at the table. The goal of studying mixed strategies is to understand the shape of a balanced range — which hands always raise, which hands always fold, and which hands live in the middle where mixing matters.

How Position Changes Everything

The most important variable in any preflop range chart is position. Ranges are not fixed — they shift dramatically depending on where you sit at the table and what has happened before the action reaches you.

Opening Ranges Get Wider as Position Improves

Early position (UTG, UTG+1): The tightest ranges. You will face action from many players behind you, so you need hands that play well even when called from multiple directions. Think top 10–15% of hands.
Middle position: Slightly wider. You have fewer players left to act and can add more suited connectors and smaller pocket pairs.
Cutoff and Hijack: Noticeably wider still. You are close to the button and can profitably open hands like suited one-gappers and weak kings.
Button: The widest opening range. You will always act last postflop, which is a massive positional advantage. Solvers open roughly 40–50% of hands from the button.
Small blind: Tricky. You act last preflop but first postflop, which reduces the value of your wide range. Ranges here are often tighter than the button but structured differently.
Big blind: You are the last to act preflop and often getting good odds, so the big blind defends (calls or 3-bets) more hands than any other position.

3-Bet and Calling Ranges Also Shift

When someone else opens before you, the chart changes entirely. Facing a UTG open, you 3-bet only premium hands. Facing a button open, your 3-bet range can include a much wider set of hands because the button is opening wide and you have position over most of the field.

Stack depth matters too. Short-stacked (under 25 big blinds), mixed strategies largely disappear — you are moving closer to push-fold, where the math is simpler. Deep-stacked (100+ big blinds), ranges become more complex because implied odds and postflop play matter much more.

Common Starting Ranges to Know

If you are just getting started, a few anchor points help:

UTG open: Something like {QQ+, AKs, AKo} is always in; {99, TT, JJ, AQs, AQo} are usually in; {77, 88, AJs, KQs} are on the edge.
Button open: Roughly any two broadway cards, all pocket pairs, most suited aces, many suited connectors down to 54s, and some offsuit broadways.
Big blind defense vs. button: Very wide — you are often getting 3:1 on your call, so the bar for folding is low.

These are starting points, not rules. A solver will show you the precise frequencies that make each range balanced, which is why interacting with the grid directly is so valuable.

How to Practice

Reading about range charts only gets you so far. The fastest way to internalize the grid is to interact with it. Try the GTO Lab interactive demo to click through positions and bet sizes and watch how the chart shifts in real time — seeing the ranges change as you move from UTG to the button is much more memorable than reading a description of it.

When you are ready to take ranges away from the screen, download the free GTO Lab preflop charts for common spots. Having a physical or printable reference while you study helps you build recall faster.

What to Focus On

When you first open a range chart, resist the urge to memorize every cell. Instead, look at the shape:

Where are the “always raise” hands? These anchor the range.
Where does folding start? This tells you how tight the position is.
Which hands are mixed? These sit on the boundary of profitability — useful to know, but not the first thing to learn.

Over time, your eye will get faster at reading these charts and you will start recognizing familiar shapes across different positions and bet sizes.

The 13×13 grid is the foundation of GTO study. Master the anatomy and you will find every other piece of poker strategy clicks into place faster.

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