Big O Calculator: 5-Card Omaha Hi-Lo Equity
Free Big O and Omaha Hi-Lo equity calculator · high, low, scoop and quarter odds · 2–6 players · 8-or-better low qualifier
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Set 5 cards for each player and click Calculate
15,000-trial Monte Carlo · up to 6 players
Big O: five cards, split pots, different hand values
Big O is five-card Omaha played hi-lo with an 8-or-better qualifier. The best high hand takes half the pot; if anyone makes a low of five different ranks all eight or lower, the best low takes the other half. When no low qualifies, the high hand takes everything. As in every Omaha game, each half of your hand must use exactly two hole cards and exactly three board cards — and you may use a different pair of hole cards for the high and for the low.
How the low works
- The ace counts as the lowest card, so A-2-3-4-5 (“the wheel”) is the best possible low.
- Five different ranks are needed: a pair kills a low.
- Straights and flushes do not count against a low — the wheel can win both halves.
- Lows are compared from the highest card down, so 8-6-5-4-3 beats 8-7-4-3-A. The usual shorthand is to read them as numbers: 86543 is lower than 87432.
- At least three board cards must be eight or lower for any low to exist. That happens on 71.7% of five-card boards (exact: 1,862,976 of the 2,598,960 possible boards).
Quartering: the trap of a shared low
If two players hold the same best low — easy when both hold A-2 — they split the low half between them and each collects a quarter of the pot. Put money in with only a low draw against an opponent who may hold the same cards, and you are often risking a full stack to win a quarter. The calculator above shows each player's low share and how often they scoop, so you can see quartering rather than guess at it.
Computed examples
200,000simulated runouts each, from preflop, with this calculator's engine. Equity is the share of the whole pot: the high share plus the low share.
| Hand | Equity | High | Low | Scoops |
|---|---|---|---|---|
| A♠ 2♠ 3♥ 4♥ K♦ | 60.7% | 27.3% | 33.4% | 46.1% |
| K♣ K♥ Q♣ Q♦ J♠ | 39.3% | 39.3% | 0% | 24.7% |
In split-pot Omaha, a hand that can win the low half and still make high hands is worth far more than big pairs that can only play for high.
A qualifying low was made on 66.8% of runouts in this matchup.
| Hand | Equity | High | Low | Scoops |
|---|---|---|---|---|
| A♠ A♥ 2♠ 3♥ K♦ | 59.8% | 39.3% | 20.5% | 43% |
| 9♣ 8♣ 7♦ 6♦ 5♠ | 40.2% | 34% | 6.2% | 23.3% |
Aces with A-2-3 play for both halves; the rundown's low cards are too high to make the best low often.
A qualifying low was made on 53.4% of runouts in this matchup.
| Hand | Equity | High | Low | Scoops |
|---|---|---|---|---|
| A♠ 2♥ 7♦ 8♣ 9♠ | 46.2% | 34.5% | 11.7% | 33.9% |
| A♦ 3♣ 4♠ 5♥ K♥ | 53.8% | 38.8% | 15% | 41.5% |
A-2 is the best two-card start for low, but A-3-4-5 is the favourite: four cards that work together give it backup lows when an ace or deuce lands on the board, and more wheel straights for the high.
A qualifying low was made on 53.4% of runouts in this matchup.
| Hand | Equity | High | Low | Scoops |
|---|---|---|---|---|
| A♠ 2♠ 3♥ K♥ | 57% | 28% | 29.1% | 42.5% |
| K♣ K♦ Q♠ Q♥ | 43% | 43% | 0% | 28.5% |
The same lesson in 4-card Omaha Hi-Lo: a premium low hand is the favourite over big high-only pairs.
A qualifying low was made on 58.2% of runouts in this matchup.
What this means for hand selection
A hand that can only win the high half is playing for half a pot most of the time, while a hand with A-2 or A-3 plus high-card support can win both. That is why big pairs are worth so much less in Big O than in PLO, and why an ace with a deuce and a third low card is the backbone of a playable hand. Low cards that duplicate each other are worth less than they look: if the board pairs your deuce, or another player holds the same A-2, the low half is split or gone.
Big O vs 5-card PLO vs Omaha Hi-Lo
Big O and 5-card PLO are dealt identically — five hole cards — but 5-card PLO is high-only, so the same five cards can be a strong hand in one game and a weak one in the other. Omaha Hi-Lo is the four-card version of the same split-pot rules; switch the card count at the top of this calculator to run it. For high-only Omaha use the PLO equity calculator (4, 5 and 6-card).
Background reading: 5-card PLO strategy · what is Omaha poker? · who wins this showdown?
Frequently asked questions
What is Big O in poker?›
Five-card Omaha played hi-lo with an 8-or-better qualifier. Each player gets five hole cards, the best high hand wins half the pot, and the best qualifying low — five different ranks, all eight or lower, with the ace counting low — wins the other half. If no low qualifies, the high hand takes the whole pot.
How is Big O different from 5-card PLO?›
The deal is identical; the winning conditions are not. 5-card PLO is high-only, so the best high hand takes everything. Big O splits the pot with a qualifying low, which makes hands containing an ace and a deuce far more valuable and big high-only pairs much less so.
What is the best low hand in Big O?›
A-2-3-4-5, the wheel. Lows need five different ranks all eight or lower, the ace plays low, and straights and flushes do not count against a low — so the wheel can win the low half and the high half at the same time.
How often does a low qualify in Big O?›
At least three board cards must be eight or lower for any low to be possible, which happens on 71.7% of five-card boards (1,862,976 of 2,598,960). Whether a low is actually made then depends on the players' cards; this calculator reports the share of runouts with a qualifying low for the exact hands you enter.
What does it mean to be quartered?›
Two players holding the same best low split the low half, so each takes a quarter of the pot. It is the most common way to lose money with a low draw: you risk a full stack to win 25% of the pot. The calculator shows each player's low share so you can see how often it happens.
Does this calculator do 4-card Omaha Hi-Lo too?›
Yes. Switch the card count at the top to 4-Card for Omaha Hi-Lo (Omaha 8 or better). The same split-pot rules and the same 8-or-better low qualifier apply.
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