Big O Rules
Big O is five-card Omaha played Hi-Lo, eight-or-better for the low. It plays like Omaha Hi-Lo (PLO8) with one big change: you are dealt five hole cards instead of four. You still use exactly two hole cards and three community cards, but the extra card makes strong high hands and qualifying lows dramatically more common — so the nuts, and the ability to scoop both halves, matter more than ever.
A quick note on rules
Big O is widely spread in US live cash rooms and its rules are well settled in that community, but it is not a fixed casino standard everywhere — a few houses tweak the low qualifier or spread a variant with a different card count. The rules below describe the standard eight-or-better, five-hole-card game. When in doubt, confirm the qualifier and card count posted at the table.
The objective
Win as much of the pot as you can — ideally both halves. The pot splits between the best high hand and the best qualifying low, so the strongest position is a hand that can scoop. Because the fifth hole card gives you more two-card combinations to work with, playable hands that make both a big high and a strong low are the ones worth chasing.
How a hand plays out
Five hole cards, then bet
Post the blinds and deal each player five cards face down. The first betting round follows, almost always with Pot-Limit betting. Those five private cards are yours alone; the extra card versus Omaha is what defines the game.
Flop, turn, river
Five community cards arrive in the usual stages: a three-card flop, then the turn, then the river, with a betting round after each. The board is shared by everyone at the table.
Two hole cards, exactly
At showdown you must use exactly two of your five hole cards and exactly three community cards for your high hand — and, separately, exactly two hole cards and three board cards for your low. The pairs you use for high and low can differ.
Because you have ten two-card combinations to draw from instead of Omaha’s six, made hands and qualifying lows show up far more often. Nut hands are the currency of Big O; a non-nut low or a second-best flush is a real trap.
How the pot splits
The scoop (best outcome)
One player takes the whole pot by holding both the best high hand and the best qualifying low, or the best high when no low qualifies. Scooping is the goal — the fifth hole card makes hands that can win both halves the most valuable holdings in the game.
The high half
The best five-card high hand — using exactly two hole cards and three board cards — wins half the pot. Standard poker rankings apply, and with five hole cards nutted highs like the nut flush and full houses arrive more often than in Omaha.
The low half
The best qualifying low — five unpaired cards all eight or lower, aces playing low — wins the other half. Straights and flushes do not count against a low, so the wheel 5-4-3-2-A is the best possible low. If no one qualifies, the high hand scoops.
Lows are read from the highest card down, and the lower hand wins, so 6-4-3-2-A beats 6-5-3-2-A. Ties on either half chop that half again between the tied players.
A worked example
The board reads A♠ 8♠ 5♥ 3♣ K♠. Dana holds Q♠ J♠ 7♦ 4♥ 2♦.
For the high, Dana uses Q♠ J♠ with the A♠ 8♠ K♠ on the board to make the nut flush in spades — ace-high, unbeatable here.
For the low, she switches to a different pair of hole cards — 4♥ 2♦ — and uses the A♠ 5♥ 3♣ from the board to make 5-4-3-2-A, the wheel, the best possible low.
The nut flush wins the high half and the wheel wins the low half, so Dana scoops the entire pot — using one pair of hole cards for high and a completely different pair for low, exactly as Big O allows.
Tips for beginners
Play for the scoop. In a split game the money is made by winning both halves, and with five hole cards the hands that can do it — think ace-deuce for the low alongside big suited high cards — come along often. Coming in with only half the pot in sight is how the extra card quietly costs you money.
Respect the nuts. Because everyone has more combinations, second-best hands are much more expensive than in Omaha Hi-Lo. A non-nut low can be counterfeited or tied, and a non-nut flush is regularly beaten. When the board gets dangerous, ask whether your hand is actually the best, not merely good.
Frequently asked questions
How is Big O different from Omaha Hi-Lo?
Big O deals five hole cards instead of four, but is otherwise the same eight-or-better Hi-Lo split as Omaha Hi-Lo (PLO8). The extra card makes strong highs and qualifying lows far more common, so the nuts win more of the time and second-best hands cost more.
How many hole cards must I use?
Exactly two, always — the same rule as Omaha. You use exactly two of your five hole cards plus exactly three community cards for your high hand, and separately exactly two hole cards plus three board cards for your low. The two you pick for high and for low can be different pairs.
What qualifies as a low?
A low is five unpaired cards all ranked eight or lower. Aces play low, and straights and flushes do not count against a low. The best low is the wheel, 5-4-3-2-A. If no one makes a qualifying low, the best high hand scoops the entire pot.
What does it mean to scoop?
Scooping is winning both halves of the pot with one hand — the best high and the best low, or the best high when no low qualifies. Because a single player can use different hole-card pairs for each half, Big O rewards hands that can win high and low at once.
What betting limit is Big O played at?
Almost always Pot-Limit, and it is usually written PLO Big O or just Big O. The extra hole card makes hands run closer together, so Pot-Limit keeps the game about post-flop skill rather than pre-flop all-ins.
Related games
Informational only — this guide explains how the game is played and doesn't mean it's offered on Salty Poker.