Sizing Preflop 3-Bets

Since I haven't offered much lately to help readers improve their game, I'd like to talk about 3 betting preflop. If you're playing $25NL or higher, you should hopefully be at the point where when an open raise is made, you can put the raising individual on a range (sometimes a reasonably precise one using their PFR% if you have enough hands played against them). 3 betting (raising this initial open raise, for those unfamiliar), is important because it allows us to do two things:
(1) Play a big pot with our big hands.
(2) Have fold equity preflop and often take down a small pot right there.

However, as with most things in poker, it's more complicated than that. The size of our raise is extremely important. This should actually be fairly obvious given the two points above - you want to raise enough to build a pot, and you want to raise enough to have some fold equity. Perhaps the most important factor when considering raise size however, is that it needs to be a size so that your opponent calling is a -EV decision based on his range.

Lets consider a typical 13/7 TAG (nitty, but pretty standard for $25NL or $50NL) open raising to a standard $2 (50c BB, no callers in front) from middle position. Both us and the villain have $50 stacks. Lets say that we are on the BU with QQ. This is a great spot for us to 3 bet because we have a strong hand that is ahead or racing with much of his range, we can get some fold equity, and if this reasonable player repops us we can avoid stacking off to AA/KK as we might if we were just to call behind and flop an overpair. In all, this is a standard spot for us to be 3-betting, and should do so every time. Of course, this would not be a good spot to 3 bet if our opponent was a 7/2 ubernit over a large hand sample - in such a case we should probably be calling with our QQ for set value, and getting away from it if we flop an overpair and our opponent shows aggression.

So, what is our opponents range? From MP it is probably something like (88+, AJs+, AQo+). Now, the key to threebet sizing is that we want to make calling a -EV move for our opponent for the hands in his range that don't crush us. At the same time, we don't want to bet so much that if he repops us with his AA/KK, we are losing much more than we need to. The villain has raised to $2 and has $48 left behind. Consider the medium pairs 88-JJ in our villain's range, which we crush. We do not want to give our opponent odds to setmine against us, which makes a small raise here very bad. Based on the 5/10 rule of setmining (I deal with this in a previous post somewhere), if we raise $5 (10% of effective stacks) it's a clear fold (or -EV call) for the villain, whereas a raise of $2.50 (5% of effective stacks) is a clear call (+EV call to setmine). A raise of right in the middle between $5 and $2.50 to $3.75 is likely a marginally +EV call for the villain given the circumstances. We don't want to risk more than we have to in case of getting repopped by AA/KK, so an appropriate 3-bet size here is to raise his $2 bet $5 to $7 total.

Note that if we had AKo in the hand above, we should be playing it the same way. Even though we are racing against the medium size pocket pairs and instead are crushing AJs, AQs and AQo, our villain is playing against our range and we still do not want to give him odds to setmine - and thus the exact same raise size would be appropriate.

Below is an example of where a villain does a very poor job of sizing his 3-bet, and gets owned by me. Notice that based on the 5/10 rule and the dead money in the pot (along with the increased chance of him stacking off if I hit my set), him raising only 6.7% of the effective stacks makes calling a pretty clear +EV choice for me.

Villain is a 16/7/3 regular over a sample of 500+ hands.

Poker Stars, $0.25/$0.50 NL Hold'em Cash Game, 9 Players
Hand History Converter by Stoxpoker

Hero (BTN): $60.25 (120.5 bb)
SB: $66.50 (133 bb)
BB: $67.80 (135.6 bb)
UTG: $23.40 (46.8 bb)
UTG+1: $56.10 (112.2 bb)
MP1: $33.55 (67.1 bb)
MP2: $12.75 (25.5 bb)
MP3: $30.85 (61.7 bb)
CO: $46.75 (93.5 bb)

Pre-Flop: Hero is BTN with 5 5
UTG calls $0.50, 2 folds, MP2 calls $0.50, 2 folds, Hero raises to $3, SB raises to $7, 3 folds, Hero calls $4

Flop: ($15.50) 2 6 5 (2 players)
SB bets $6, Hero raises to $17, SB raises to $59.50 and is all-in, Hero calls $36.25 and is all-in

Turn: ($122) 8 (2 players, 2 are all-in)
River: ($122) 7 (2 players, 2 are all-in)

Results: $122 pot ($3 rake)
SB showed K K (a pair of Kings) and lost (-$60.25 net)
Hero showed 5 5 (three of a kind, Fives) and won $119 ($58.75 net)