The Big Blind is a defensive position — you close the action preflop and get a discount to call. GTO defends wide vs small opens (especially from the BTN) but knows when to fold vs tight UTG ranges. Mastering BB defense is the fastest win-rate boost for most players. At 40bb you are in the mid-stack zone — deep enough for postflop play but shallow enough that implied odds are reduced. GTO tightens slightly vs 100bb, cutting speculative hands like small suited connectors that need deep stacks to realize equity. Below is the GTO range grid for BB at 40bb (6-max, rake 5% cap $3) — green = raise, amber = call, red = fold. Hover any hand for exact frequencies and EV.
76.9%
Raise (130)
0.0%
Call (0)
23.1%
Fold (39)
Hover or tap a hand to see GTO action, frequencies, and EV.
Pre-computed with TexasSolver · 0.5% exploitability · Rake 5% cap $3 · 6-max
| Action | Hands | Frequency | Avg EV (bb) |
|---|---|---|---|
| Raise | 130 / 169 | 76.9% | 1.44 bb |
| Call | 0 / 169 | 0.0% | 0.00 bb |
| Fold | 39 / 169 | 23.1% | 0.11 bb |
From the Big Blind, defend wide vs BTN/SB opens (call with any suited hand, most offsuit broadways, and pairs), but fold more vs UTG/HJ. Vs a 2.5x BTN open at 100bb, GTO defends ~55–60% — if you fold more, regs exploit you by opening 100%. Mid-stack strategy: you can still open-raise normally, but size down 3-bets and avoid calling 3-bets with speculative hands. Pairs and suited broadways go up in value; small suited connectors go down.
Pro tip: BB defense is the #1 leak for microstakes players. If you fold BB vs BTN more than 45% at 100bb, regs print money against you. Study which suited hands GTO calls and why.
GTO open-raise frequency for BB at 40bb depends on rake and field, but our TexasSolver-based chart (0.5% exploitability, 5% rake cap $3) shows the solver-preferred raise/call/fold mix for all 169 hands. Hover the grid above for exact frequencies per hand. Generally, BB is defensive (call-heavy vs steals) — see the grid for 40bb specifics.
Use the 3-step method: (1) Quiz yourself — cover the grid and ask 'What does GTO do with AJo BB 40bb?' (2) Check and note surprises. (3) Drill the borderline hands (the amber/mixed cells) with Lab's spaced-repetition drills. 10 minutes a day per position beats cramming.
These ranges are solved for 6-max cash, 5% rake cap $3, which matches most micro-to-mid stakes online games. At very low stakes with high rake or vs extremely tight/loose opponents, exploitative adjustments beat pure GTO — but you need to know GTO first to know when to deviate. See our Methodology for solver details.
No. This chart is for post-hand study only. Using any solver chart or AI assistance during live play violates PokerStars and GGPoker Terms ofService and risks account bans and fund seizure. Study off-table, play your A-game on-table.
Free preflop charts and leak fixes — no spam.