EV (Expected Value) thinking là nền tảng của rational poker decisions. Mọi action good hoặc xấu đều có thể quantified bằng EV. Bài này đi sâu vào cách tính EV cho các situations phổ biến — từ simple call decisions đến complex bluff scenarios.
EV Formula Cơ Bản
Formula Chung
EV = (Probability Win × Amount Won) - (Probability Lose × Amount Lost)
Kết quả:
- EV > 0: Profitable action → do it
- EV < 0: Losing action → avoid (unless strategic meta-game reason)
- EV = 0: Break-even
Ví Dụ 1: Tính EV Của Call
Tình Huống
River. Pot: $100. Opponent bets $50.
You have bluff catcher. Estimate opponent bluffing 40% of time.
Should you call?
Tính Toán
Nếu bạn CALL:
When they bluff (40%): Win $150 (pot $100 + their bet $50) When they value bet (60%): Lose $50 (your call)
EV(Call) = (0.40 × $150) - (0.60 × $50)
= $60 - $30
= +$30
Call has EV = +$30 → Call is correct.
So Sánh Với Fold
If you fold: EV = $0 (you keep your $50)
But: The fold EV is relative — by folding instead of calling, you're giving up +$30 EV.
Net of Call vs Fold: +$30 better than fold → Call.
Ví Dụ 2: Tính EV Của Bet For Value
Tình Huống
River. Pot: $100. You have top pair top kicker.
Option A: Bet $75. Option B: Check (opponent checks behind 90% of time, bluffs 10%).
Assume when you bet $75:
- Opponent calls with better hand 20% of time (you lose)
- Opponent calls with worse hand 40% of time (you win)
- Opponent folds 40% of time (you win pot)
EV(Bet $75)
When better hand calls (20%): Lose $75
When worse hand calls (40%): Win $175 ($100 pot + $75 call)
When folds (40%): Win $100 (pot)
EV = (0.40 × $175) + (0.40 × $100) - (0.20 × $75)
= $70 + $40 - $15
= +$95
EV(Check)
When opponent bluffs (10%): Win $100 pot after check-calling
When opponent checks back (90%): Win pot at showdown 50% (you have TPTK)
EV(check) ≈ 0.10 × ($100 + their bluff size) + 0.90 × (0.50 × $100 - 0.50 × 0)
For simplicity: EV(Check) ≈ $45-55 (rough estimate)
Bet $75 >> Check: +$95 vs. ~$50 → Bet is clearly better.
Ví Dụ 3: EV Của Bluff
Tình Huống
River. Pot: $100. You have nothing (missed draw).
Option: Bet $75 as bluff. Opponent folds 55% of time.
EV(Bluff $75)
When opponent folds (55%): Win $100 pot
When opponent calls (45%): Lose $75 bluff
EV = (0.55 × $100) - (0.45 × $75)
= $55 - $33.75
= +$21.25
Bluff has EV = +$21.25 → Profitable bluff.
What Fold Frequency Makes Bluff Break-Even?
Set EV = 0:
(x × $100) - ((1-x) × $75) = 0
100x - 75 + 75x = 0
175x = 75
x = 75/175 = 0.4286 = 42.86%
Need opponent to fold 43%+ for bluff to be profitable.
If folding less than 43% → bluff is -EV → don't bluff.
Ví Dụ 4: EV Của Set Mining
Tình Huống
You have 66. Opponent bets 3BB preflop (pot = 4.5BB with antes/blinds).
If you call:
- Flop a set: ~12% chance
- When you flop set: Win average 8BB post-flop (implied odds)
- When you don't flop set: Fold (lose 3BB)
EV(Call To Set Mine)
EV = (0.12 × 8BB) - (0.88 × 3BB)
= 0.96BB - 2.64BB
= -1.68BB
This call is -EV at these numbers!
What Implied Odds Needed?
Need EV ≥ 0:
0.12 × X - 0.88 × 3BB = 0
0.12X = 2.64
X = 22BB
Need to win 22BB when hitting set for call to break even.
Rule of thumb: Need ~15x implied odds (call 3BB → need to win 45BB when hit).
Ví Dụ 5: EV Của Squeeze Play
Tình Huống
UTG opens 2.5BB. MP calls. You squeeze to 9BB from BTN.
UTG folds 60%. MP folds 65%.
When you get called by either:
- Estimate your equity post-flop = 35% (you're behind)
- Average pot when called = 20BB (net of remaining stacks)
EV(Squeeze 9BB)
Fold scenarios:
Both fold (60% × 65% = 39%): Win 4.5BB (blinds + UTG open + MP call) UTG folds, MP calls (60% × 35% = 21%): Go post-flop, equity-based EV UTG calls, MP folds (40% × 65% = 26%): Go post-flop Both call (40% × 35% = 14%): Go post-flop multiway (worst)
Simplified EV when called (any scenario):
Post-flop EV ≈ 0.35 × pot - 0.65 × (remaining invested)
Full calculation complex but:
Key insight: If both fold 39% → win 4.5BB pure.
EV from fold equity alone:
0.39 × 4.5BB = 1.755BB
Plus post-flop EV (positive when in position) → overall squeeze is likely +EV.
Running EV Calculations Practically
You Don't Need Exact Math In Game
Poker decisions happen quickly. You can't do full EV calculations at the table.
Instead: Build intuitions from off-table study.
Off-table: Calculate many spots → internalize patterns. In-game: Apply pattern recognition, not full calculation.
EV Shortcuts
Rule for calling on river:
Opponent bets X into pot P. Your break-even equity = X / (P + X + X) = X / (P + 2X)
Bet 1/3 pot = need 20% equity Bet 1/2 pot = need 25% equity Bet pot = need 33% equity
Rule for bluffing:
Bluff break-even fold % = BetSize / (Pot + BetSize)
Bluff 1/3 pot → opponent must fold 25%+ Bluff 1/2 pot → fold 33%+ Bluff pot → fold 50%+
Long-Term EV Thinking
One Hand vs. Many Hands
EV is a long-run concept. Individual hand results are noise.
Example:
You have correct +$30 EV call. You call. They show value hand. You lose.
This hand result: -$50 EV was still: +$30
In the long run, making this call 1000 times = +$30,000. Individual variance doesn't change EV.
Tilt Is EV Destruction
When tilting → making -EV decisions that "feel" like revenge.
Tilt EV calculation:
Normal session EV: +5BB/100 Tilting session EV: -20BB/100
If you tilt 2 hours per 10-hour session:
True EV = (8/10 × 5) + (2/10 × -20) = 4 - 4 = 0
Tilting 20% of time wipes your entire edge.
Fix: Stop when tilting. Protect your EV.
Kết Luận
EV calculations are the language of poker logic:
- Every decision has an EV
- Maximize EV = maximize long-run profit
- Shortcuts exist for common situations (break-even equity, break-even fold %)
- Off-table practice builds in-game intuition
- Variance doesn't change EV — stay disciplined through short-run results
Start calculating EV for hand histories off-table. Over time, this thinking becomes automatic — and every table decision becomes more grounded in math than guessing.