21 Common Poker Leaks, Ranked by What They Cost You

You didn't punt. That's the part that stings. There was no cooler worth retelling, no hand where you got it in good and watched a two-outer land, nothing you could point at and say that one, right there, that's where the night went. You just finished down two buy-ins, and if someone asked you which hand did it, you'd have nothing to give them.

The most common poker leaks are the small repeated decisions that come up ten or more times per 100 hands: over-folding the big blind, open-limping, opening too wide from early position, c-betting every flop at the same size, and calling down too light on the turn. None of them feels like a mistake while you're making it. That's exactly why they survive.

Short answer: The most common poker leaks, ranked by cost, start with over-folding the big blind, open-limping, and auto-c-betting every flop at one size. Leaks that hit you 10 or more times per 100 hands cost more over a year than the dramatic river mistake you make once a night, because the loss compounds over volume.

Key takeaways

• A leak is a repeated decision pattern that loses money over a large sample, not a single bad hand.
• Cost equals how often the spot comes up multiplied by how much you give away each time. Most leak lists ignore the first half completely.
• At 6-max you're in the big blind on roughly 17 of every 100 hands, which is why blind leaks outrank almost everything else.
• No public dataset assigns a bb/100 figure to each individual leak. Anyone printing one to the decimal made it up.
• Fix your leaks in exposure order, not in the order they hurt your feelings.

What is a poker leak, exactly?

A poker leak is a repeated decision pattern that loses money over a large sample. PokerNews defines it as "a consistent strategic mistake that a player makes," and the load-bearing word there is consistent. One bad call on a Tuesday isn't a leak. The same bad call in the same spot, every time that spot appears, is.

Three things get confused constantly, so here's the split:

• A bad beat is a hand you played correctly and lost anyway. It costs you money and teaches you nothing.
• A one-off mistake is a decision you got wrong once, usually because you were tired or distracted.
• A leak is the same wrong decision, in the same spot, every time it comes up.

The test is simple: if you can describe the spot without naming the cards, it's a leak. "I fold too much when the button raises my big blind" is a leak. "I lost with kings" is a Tuesday.

How do you rank poker leaks by what they cost?

Rank leaks by frequency times magnitude: how often the spot comes up per 100 hands, multiplied by how much expected value you give away each time it does. Expected value (EV) is the average amount a decision wins or loses over the long run. bb/100 is the standard unit, meaning big blinds won or lost per 100 hands.

The frequency half is just arithmetic. At 6-max you're in the big blind on roughly 17 of every 100 hands, and the small blind on another 17. At a 9-handed live table it's closer to 11 each. Nobody folds their way out of that.

The magnitude half is measurable, and GTO Wizard has published the clearest worked examples of it. In their article on which mistakes cost you the most money, folding J6s in the big blind where the solver calls is a 0.26bb error, which they describe as a 26 bb/100 mistake. Opening A9o from a seat where the solver opens ATo is a 0.14bb error. A wrong turn bet size with KJs runs to 0.87bb. Their framing matters as much as the numbers: those figures are the cost per time you face that exact spot, not per 100 hands you play.

Here is what we're not going to do. We are not printing a bb/100 figure next to each of the 21 leaks below, because no public dataset contains one. Nobody has run a study that isolates "open-limping" across a tracked population and reports its cost with a decimal point. Sites that publish those numbers are making them up, and a poker audience can smell it. What we can do honestly is sort the leaks into three tiers by exposure and error size:

Constant bleed: the spot hits you 10 or more times per 100 hands and you're getting a whole action wrong. Small error, enormous volume.

Big pot: the spot shows up a few times per 100 hands, but the pot is already large, so each error is worth most of a stack over time.

Session: not a hand decision at all. A state of mind or a game selection problem, invisible in a hand history, and capable of costing more in one night than the other twenty leaks cost in a month.

What are the most common poker leaks?

The 21 most common poker leaks, ordered by exposure within each tier:

Which of these leaks costs the most?

Over-folding the big blind is the most expensive leak in low-stakes poker, and it isn't close. The reason is pure exposure. You're in that seat on one hand in six at 6-max, you already have a big blind in the middle, and every time you fold a hand the solver would defend you hand the raiser a pot he didn't have to fight for. GTO Wizard's J6s example puts one such fold at a 0.26bb error in that spot. Now multiply by how many times a night you face a button open.

There's an honest caveat that most articles skip: at micro stakes the rake takes a slice of every pot you win, which makes the thinnest defends less profitable than a rake-free solver output implies. The correct adjustment is to defend slightly tighter than the chart, not to fold 70% of your big blind and call it discipline.

Second place goes to open-limping, for a different reason. Limping doesn't just lose EV in the hand you limp, it removes your ability to win the pot uncontested preflop, and it invites three players to see a flop in position against you. You can be the best postflop player at a $1/$2 table and still get quietly dismantled by playing every pot as the caller.

Third is the c-bet autopilot. Betting two thirds of the pot on every flop you raised into is the single most common postflop pattern at low stakes, and it's the one that population data punishes hardest. If you're going to bet a board, know what you'd do on the turn first.

Notice that the leaks with the loudest reputation are not the ones bleeding you. Nobody at your table is losing their roll to a bad hero call, however good the story sounds afterwards. The money leaves in the boring spots, ten times an hour, and Mike McDermott isn't walking in to pay that man his money on your behalf.

Do preflop or postflop leaks cost more?

Preflop leaks cost more in total; postflop leaks cost more per decision. Both halves of that are supported by GTO Wizard's published figures: a wrong preflop open runs around 0.14bb in the spot, while a wrong turn sizing with the same hand class runs 0.87bb. The turn error is six times bigger. You just face six times fewer of them.

There's a second axis worth knowing, because it changes what you drill first. GTO Wizard's analysis states that a bad call is more costly than a bad bet, because a call has to win at showdown, and that errors get more expensive the later in the hand they happen, because the pot is bigger. So the ranked cost order inside any single street is roughly: bad calls, then bad folds in big pots, then bad sizings.

Population data backs the direction of the most common postflop errors. In a July 2026 Upswing Poker breakdown of 2025 tracked data from 500nl to 10000nl, even winning professionals over-folded against delayed continuation bets by 11% versus the solver baseline at the smallest size, and under-bluffed rivers in multiway pots by 11 to 16 percentage points. Those are regs. If the pros in that sample are over-folding and under-bluffing by that much, the odds that you aren't are not good.

How do you find out which of these 21 leaks you actually have?

Run a one-week audit. You don't need a tracker or a HUD for this, and if you play live or on your phone you don't have one anyway.

1. Write down the three spots that make you uncomfortable. Not the spots you lose the most in, the ones where you genuinely don't know what you're supposed to do. Discomfort is a reliable pointer, because leaks live where you have no plan.
2. Mark every hand you play in those three spots for one week. Marked hand, one line of note, nothing more. "BB vs BTN open, folded T8s" is enough.
3. At the end of the week, count. How many times did the spot come up, and what did you do each time? A pattern that shows up 40 times in a week is a leak. A spot you hit twice is a hobby.
4. Compare the pattern, not the hands, against a solver-backed baseline. You're looking for direction: too tight or too loose, too passive or too aggressive. Our plain-English guide to GTO poker covers what that baseline is and what it isn't.
5. Take the top row only. One leak. The five-step framework for fixing poker leaks walks through the measure, compare, drill, re-measure loop for the one you picked.

If you'd rather not do the counting by hand, this is exactly what LeakSeek's leak report is for: it tracks the mistakes you make across completed drills and ranks them by EV loss, which is the ordering this whole article argues for. A worked example of what that breakdown looks like on a single hand is here.

How to actually drill this

Reading a list of 21 leaks changed nothing yet. You now know the name of your problem, which feels like progress and isn't. Knowing you over-fold the big blind while continuing to over-fold the big blind is just the cartoon dog sitting in the burning room with a diagnosis. Leaks are habits, and habits don't respond to information. They respond to reps.

1. Pick one leak from the constant bleed tier. Not three. If you're guessing, take number 1, because the exposure math makes it the right default for almost everyone at 6-max.
2. Run 20 reps of that exact spot, five days a week, for two weeks. (Yes, I'm an EV doctor) Twenty reps takes about five minutes. Do them on the commute, in a queue, before you sit down to play.
3. You're done when the spot stops feeling like a decision. That's the observable change: the hand comes up in a real session, and you act without the pause. If you're still tanking on hand 200, you're drilling a slightly different spot from the one costing you money. Narrow it and go again.

That last mile is the whole reason LeakSeek exists: real spots, instant solver-backed feedback, five minutes at a time, with the drills tied to the leaks you keep repeating. It's phone-only and there's no free access to the internal solver (yet), so if you want to build your own sims you'll need something else on the side. Our roundup of poker training apps and the head-to-head tool comparisons cover what those are.

Most players will read this, nod at number 8, recognize themselves, and go play 400 hands tonight without changing a thing. That's the actual leak. You've now got the list, the tiers, and a two-week protocol, so the only thing left between you and a better win rate is the deeply unglamorous business of doing 20 reps on a Tuesday.