Fold to probe (turn and river)

What it measures

Fold to probe is the answer to a probe bet. A player raised preflop (or c-bet the flop), then checked back the next street. On the following street, someone out of position bets before they act. Fold to probe is how often they let it go.

A turn example: Cara opens from the cutoff, Dev calls in the big blind, and the flop goes check, check. Dev bets the turn into Cara. If Cara folds, that’s a fold to probe; a call or a raise is a chance without a fold.

The neighbors are easy to mix up. Fold to c-bet runs the other way: a player facing the raiser’s bet. Fold to stab is the raiser checking on this street and folding to an in-position bet; fold to probe is about a check on the street before. And fold vs bet counts the first bet a player faces on a street from anyone, at any size, so it includes probes along with everything else.

How it’s calculated

Fold to probe = folds ÷ probes faced, counted separately for the turn and the river.

• A chance: they held the lead (the preflop raiser for the turn, the flop c-bettor for the river), checked the street before through (a check with no bet in front, and nobody bet), and on the next street someone bet into them before they acted.
• It counts: when their answer to that bet is a fold. A call or a raise is a chance without a fold.
• If someone raises the probe before the action reaches them, the hand isn’t counted: they’re facing a raise, not a probe.
• The street only counts when at least two players could still bet on it.

There are no splits beyond the street: one turn number and one river number.

Example: Cara checked back the flop as the raiser and then faced a turn lead 16 times. She folded 7: 7 ÷ 16 = 44%, inside the range. On the river, after checking back the turn as the flop c-bettor, she faced a lead 9 times and folded 6: 6 ÷ 9 = 67%. That shows gold, but faded, because 9 chances is under 12.

Why it matters

A check-back says something about a range. Most players c-bet their strong hands, so what they check back leans toward ace-high, small pairs and draws they didn’t want to bet. Fold to probe tells you how much of that range is willing to fight.

The bluff math is friendly. The pot after a check-back is small, and probes are often small too. A 33% pot probe needs 24.8% folds to profit as a pure bluff, and a half-pot probe needs 33.3%. A player at the bottom of the typical range, folding 30%, already makes a 33% probe with no hand profitable; a player at 55% makes any size up to about pot work.

It’s also a read on how they check back. A low number means their check-backs hold real hands: pairs checked for pot control, traps, strong draws. Against them, probe for value with hands that beat a medium pair, and expect calls.

Read it with their delayed c-bet: a player who folds to probes a lot and rarely bets the turn after checking the flop has given up on the flop, and the pot is yours to take.

Too low, about right, too high

On the turn and river

Turn: fold to probe

FPrb typical 30–55%

Most fold-to-probe chances come on the turn: the preflop raiser checks back the flop, and the big blind or another out-of-position caller leads. The checked-back range is at its widest here, full of ace-high, underpairs and missed overcards, with some pot-control pairs and traps mixed in. No money went in on the flop, so folding costs them little, which is part of why the typical range runs up to 55%.

A high turn number means they checked back with mostly air and won’t defend it. A low one means their check-backs carry pairs and draws that will call, and possibly hands waiting to raise.

How they got here matters. A raiser who c-bets nearly every flop checks back only their worst hands, so expect their turn fold to probe to run high; a raiser who checks back often keeps more pairs in the range and folds less.

Turn exploit: against a high turn fold to probe, lead about a third of the pot with every draw and every hand that can’t win at showdown. When they call, your draws still have outs. Against a low one, skip the probe with weak hands and check to them, using their delayed c-bet to decide whether to expect a bet.

River: fold to probe

FPrb typical 30–55%

The river version comes after the flop c-bettor checks back the turn. That turn check usually means one of two things: a medium hand happy to see showdown (top pair with a weak kicker, second pair) or a bluff that gave up. Facing a river lead, the first group has a bluff-catcher decision and the second has nothing to decide.

So the river number shows how their turn check-backs split. A high river fold to probe says their turn checks were mostly give-ups; a low one says they were pot control with showdown hands, and they’ll call.

With no draws left, every river probe is either value or a bluff, and the price is exact: a half-pot lead needs 33.3% folds, a pot-size lead 50%.

River exploit: if their river fold to probe is over 55%, bluff the river with your missed draws when they check back the turn; even a pot-size lead (needs 50%) can profit if their folds hold at that size. If it’s under 30%, lead the river only with hands that beat a medium pair, and bet those big.

When it’s your own number

Fold to probe has no read hint, so it won’t show as a read on your badge, but anyone studying your numbers can spot it. If you fold too often after checking back, observant players will lead into you with anything whenever you check. If you rarely fold, they’ll probe you only for value and size those leads up.

To check yours, look at it next to your flop c-bet. A high c-bet rate makes your check-backs weak, so your fold to probe climbs; that’s natural, but over 55% you’re giving away pots. The fix is in the check-back range: check back hands that can call a lead (pairs, good draws) and c-bet the misses you’d fold anyway.

Using it on the HUD

Fold to probe shows on the badge of the player who checked back, on the next street, both before and after the probe: you see it while deciding whether to lead, and again once they face your bet. On your turn, the panel also lists it when you’re out of position against the player who checked back, alongside their fold rates under each bet size button.

Turn and river are separate, both labeled FPrb, with no splits beyond the street. Colors: gold over 55%, blue under 30%, faded with fewer than 12 chances. It has no read hint, so it colors but never becomes a read sentence.

Sample size: a chance needs a check-back and then a lead, so it builds slowly. At 30% the error is ±13 points over 12 chances and ±10 over 20; at 50% it’s ±9 over 30. Read it with their fold vs bet on the same street, which fills up faster.

Questions