PokerSolver
PokerSolver/6-max · 150bb · SB 0.5bb · ante 0.16bb · 5% rake, cap 8bb/BB vs CO 4-bet 20.7bb

BB vs CO 4-bet 20.7bb

6-max · SB 0.5bb · ante 0.16bb · 5% rake, cap 8bb (blinds 0.5/1bb, ante 0.16bb) · 150bb · CO opens 3bb, BB 3-bets to 9bb, CO 4-bets to 20.7bb · Big blind to act

6-max · 150bb · SB 0.5bb · ante 0.16bb · 5% rake, cap 8bbChange game
Stacks (bb), if they differ
Pot 31.16bbYour cards?
9bb
20.7bb
0.5bb

Tap your two cards.

Big blind's range

408 of 1,326 combos get here
Fold 62.8%Call 30.8%All-in 149.84bb 6.5%
Tap a hand, or type one above, to see its exact mix.

What is the GTO play for the big blind (BB) when CO opens 3bb, BB 3-bets to 9bb, CO 4-bets to 20.7bb in 6-max · SB 0.5bb · ante 0.16bb · 5% rake, cap 8bb at 150bb?

CO opens 3bb, BB 3-bets to 9bb, CO 4-bets to 20.7bb in 6-max · SB 0.5bb · ante 0.16bb · 5% rake, cap 8bb, 150bb: the big blind (BB) folds 62.8%, calls 30.8% and goes all-in 149.84bb 6.5%. Always call: 55-QQ, AJs+, KJs+, JTs, T9s, 87s, 76s, 65s, 54s, AQo. Always all-in 149.84bb: AA. Mixed: KK, ATs, A8s, A3s-A5s, KTs, T8s, 98s, AKo.

Always fold
A6s-A7s, A2s, K2s-K9s, Q5s+, J7s-J9s, J5s, T7s, 53s, 43s, ATo, A8o, A5o, KTo+, QTo+, JTo, T9o
Always call
55-QQ, AJs+, KJs+, JTs, T9s, 87s, 76s, 65s, 54s, AQo
Always all-in 149.84bb
AA
Mixed
KK, ATs, A8s, A3s-A5s, KTs, T8s, 98s, AKo
Settings: 6-max · 150bb · SB 0.5bb · ante 0.16bb · 5% rake, cap 8bb (small blind 0.5bb, big blind 1bb, an ante of 0.16bb from every player, 150bb stacks, 5% rake capped at 8bb; no rake when no flop is dealt). Solver: HoldemResources Calculator (HRC) (HRC CI 24.4). A jackpot fee on bigger pots is not in this solve, so lines that build big pots may be slightly too loose. Bet sizes are the solved ones; a size that is not here plays like the nearest one.

Fits exactly: no game we have checked.

Close: CoinPoker cash with antes NL50 (rake before the flop in 3-bet pots there, none here).

Rake sources: the ante from 93 of our own CoinPoker hands at $0.25/$0.50 with a $0.08 ante, played 2026-09-30; the caps and the preflop rule from coinpoker.com/games/texas-holdem/, fetched 2026-10-31.