At a glance
- On the HUD
- Turn Prb·River Prb
- Formula
leads / times the player with the lead checked the street before through and they were first, out of position, with no bet in front- Typical range
20–50% on every street
- Where it shows
- Badge: players out of position after the lead checked back the street before; the prober after betting.
- Trust it after
- 12 chances. Below that the number is faded; reads need 12 chances and a number at least one standard error outside the typical range.
What it measures
When the preflop raiser checks back the flop, they give up the initiative. The player out of position gets the first move on the turn, and a bet there is a probe. The river version comes one street later: the raiser c-bet the flop, got called, then checked the turn back, and the out-of-position player leads the river.
At the table: Ana opens on the button and Ben calls in the big blind. The flop goes check, check. On the turn Ben bets before Ana can act. That’s a turn probe. Had Ben checked, Ana’s turn bet would have been a delayed c-bet.
Three stats get mixed up with it. A donk bet leads into the player who bet or raised the previous street; a probe leads into a player who checked it. A stab is the in-position version: the aggressor checks to you on this street and you bet. And the answer to a probe, from the player who checked back, is fold to probe.
How it’s calculated
Probe = leads ÷ probe chances, counted separately for the turn and the river.
- Turn setup: the preflop raiser checked the flop with no bet in front, and nobody bet the flop.
- River setup: the player who c-bet the flop checked the turn the same way: a check with no bet in front, and nobody bet the turn.
- A chance: on the next street, the player is out of position to the one who checked back, and their first action comes with no bet in front, before that player acts.
- It counts: when that first action is a bet.
- The street only counts when at least two players could still bet on it (not everyone all-in).
In multiway pots, more than one player can get a chance on the same street: if the first one checks and the next one leads, the first scores a check and the second a probe. A player who acts after someone else has already led gets no chance that street, because they face a bet. There are no splits beyond the street.
Example: Ben had 25 turn chances and led 9: 9 ÷ 25 = 36%. He had 10 river chances and led 6: 6 ÷ 10 = 60%. That river number shows gold but faded, since 10 chances is under the HUD’s 12.
Why it matters
A check-back changes the balance of ranges. Most players c-bet their strongest flops, so a raiser who checks back in position usually holds a weaker range than one who bets: lots of ace-high, small pairs and give-ups. The player out of position now has the stronger range on many turns, and probing is how they use it. A player who never probes lets the raiser see the next card for free; a player who probes everything bets hands that would do better checking.
The number changes how you play after you check back. Against a frequent prober, check back only hands that can stand a turn bet; c-bet the flop with weak hands that would fold, or accept that you’ll lose those pots. Against a rare prober, checking back is cheap: you’ll usually see the next card for free, and their lead, when it comes, means strength.
Read it alongside their donk bet and check-raise. A player who leads often in every spot just likes to lead. One who probes often but rarely donks has learned what a check-back means, and their probes are better aimed.
Too low, about right, too high
Too low: under 20%
What it says
They almost never lead after a check-back. Their default is to check again and react: check-call with medium hands, check-fold misses, sometimes check-raise. When a lead does come, it’s usually a strong made hand that wants to build the pot or a big draw. Passive players land here, and so do players who were taught that leading is always a weak play.
How to exploit it
- Check back the flop more freely in position with medium hands and draws. You’ll usually get the turn, and often the river, for free.
- When they check the turn, remember their check isn’t weakness: it holds their strong hands too. Bet for value with hands that beat a medium pair, and watch their turn check-raise.
- When they lead, believe it. Fold weak pairs and ace-high, and raise only hands that beat strong one-pair hands.
About right: 20–50%
What it says
They lead some turns and rivers after the check-back and check others, which is roughly how a thoughtful player handles the spot: probing value hands and draws on cards that suit them, checking hands that can’t stand a raise. Their leads are a mix you can’t simply fold to or always call, and their checks still hold some strong hands, so a check from them isn’t an invitation to bet everything.
How to exploit it
Defend by price. Against a half-pot probe, folding more than 33.3% of your range lets their bluffs profit on the spot (the MDF is 66.7%); against a 33% probe the MDF is 75.2%, so you should fold even less. Look for the edge in how they handle a raise: if their turn fold to raise is high, raise some probes with overcards and backdoor draws, and raise your strong hands for value since their range is wide.
Too high: over 50%
What it says
They lead most turns or rivers after a check-back. That range is wide: bottom pairs, draws, ace-high and air alongside the value. Usually it’s a player who reads every check-back as weakness and attacks it. If their aggression factor is high everywhere, it’s style; if it’s only high here, they’ve learned the spot and are probably right to use it against weak check-backs.
How to exploit it
- Give your check-back range some strength. Check back hands that can call a turn bet (top pair with a weak kicker, middle pair, gutshots with overcards) and c-bet the weak hands you’d fold.
- Call their probes wider with any pair and with good draws.
- Raise their turn probes with strong hands and your best draws. A range this wide can’t continue often.
- On the river, call down with bluff-catchers when the draws missed, especially if their river bluff (shown) is high.
On the turn and river
Turn: probe
The turn probe is the common one. It comes up whenever the preflop raiser checks back the flop and a player out of position to them is first on the turn, most often the big blind against a late-position opener. Nobody bet the flop, so the pot is still small and a probe risks little: a half-pot probe needs 33.3% folds to profit as a pure bluff, and a 33% probe needs 24.8%.
Draws are still live, so turn probes mix value with semi-bluffs: flush and straight draws, overcards with a gutshot, weak pairs betting for protection. A high turn probe means they bet those draws and thin pairs; a low one means they’d rather check-call or check-raise them.
Who checked back matters too. Against a raiser who c-bets almost every flop, a check-back is very weak and probing should work well; against one who checks back a lot, the range holds more strong hands and probes get called more.
Turn exploit: against a frequent turn prober who bets small, you need little to continue: a 33% pot bet asks for 19.9% equity. Call with any pair and most draws, then decide on the river once most of their draws have missed.
River: probe
The river probe needs a longer setup: the raiser c-bet the flop, got called, then checked the turn back. That turn check usually means a medium hand happy to see showdown, a bluff that gave up, or a slowplay. The out-of-position player leads the river into that range.
No draws are left, so river probes split cleanly into value and bluffs. Value means hands that improved on the turn or river, or that called the flop and now beat a medium pair. Bluffs are missed draws that know the checked-turn range is full of bluff-catchers. A high river probe from a player whose shown river bets are often air is a bluff-heavy lead; the same probe rate with a low river bluff (shown) is mostly value.
Chances come less often than on the turn, so the river number stays faded longer.
River exploit: as the player who checked the turn back, you hold mostly bluff-catchers. Against a high river prober, call with your medium pairs; against a low one, fold them. Big river probes from players who rarely probe are almost always value.
When it’s your own number
Probe has no read hint, so your badge won’t spell it out, but observant opponents can still use it. If you rarely probe, they can check back flops with any hand that wants a free card and fold to your leads. If you probe almost every time, they can check back stronger hands and raise you or call you down.
To check yours, compare your turn probe with the 20–50% range and with how the players you face respond, which is their fold to probe. A sound turn probing range is built from hands that want a bigger pot (top pair and better on turns that help you) plus draws, with medium pairs and showdown hands checked. Over 50%, you’re probably betting hands that want to check; under 20%, you’re handing out free cards.
Using it on the HUD
Probe shows on the badges of players out of position after the player with the lead checked back the street before, next to their check-raise, so you know how likely a lead is before they act. Once one of them leads, the prober’s badge keeps showing it, with their aggression on that street.
Turn and river are separate numbers, both labeled Prb, with no splits beyond the street. Colors: gold over 50%, blue under 20%, faded with fewer than 12 chances. Probe has no read hint, so it colors but never becomes a read sentence.
Sample size: chances only come when the player is out of position after a check-back, so they build slowly. At 30% the error is ±13 points over 12 chances and ±10 over 20, so treat a turn number as a lean until it has 20 or more. The river version takes longer.
Questions
What is a probe bet in poker?
A probe bet is a lead from out of position after the player with the lead checked back the previous street. On the turn, the preflop raiser checked the flop back; on the river, the flop c-bettor checked the turn back. The out-of-position player then bets first, attacking a range that just declined to bet.
Probe bet vs donk bet: what’s the difference?
Both are leads from out of position, but into different players. A donk bet leads into the player who bet or raised the previous street, a range that just showed strength. A probe leads into a player who checked the previous street back, a range that usually holds fewer strong hands, because most players bet those.
When should you probe the turn?
When the raiser’s flop check-back left them weak and the turn is a good card for your range. Bet value hands that want a bigger pot and draws that like fold equity; check medium pairs that would rather reach showdown. Against players with a high fold to probe, probe wider and smaller: a 33% pot lead needs only 24.8% folds.
What is a good probe bet percentage?
Inside the HUD’s typical range of 20–50% for both the turn and the river. Under 20%, a player is giving away free cards after the raiser checks back. Over 50%, they’re leading with too many hands that would rather check. Where a good player sits depends on how weak their opponents’ check-backs are.