The odds of flopping a pair with an upaired starting hand is 29% or 1 in 3.45
Pair – Quick Recap
Definition of a One Pair –
Holding two cards of identical rank.
Example – AAXXX
A Pair in Hold’em can be where we hold two cards of identical rank in our starting hand. It can also be if we pair one of our hole cards with one on the board, or we play a Pair on the board. The best Pair in Hold’em is Aces.
Odds of Making a Pair on the Flop
The odds of making a Pair on the flop depend on the type of hand we have.
Assuming two unpaired hole cards, our odds of making a Pair on the flop is 29%.
However, our overall odds of making a Pair with any starting hand is actually 31.1%.
So, why the discrepancy?
Naturally, some of our starting hands will already be pocket Pairs! This means we have guaranteed odds to make a Pair or better. Ignoring any Pairs on the board (we’ll still count our holding as One-Pair in this case), here is the breakdown for pocket-Pairs.
The Pocket Pairs - Breakdown
Weak Pair (below second card on the board) = 41.3%
Mid Pair (above second card on the board) = 23.3%
Over Pair (above top card on the board) = 23.3%
Trips and better = 12%
Naturally, the likelihood of the different types of Pair depends on the exact pocket Pair we hold, since stronger Pocket Pairs flop Over Pairs more frequently.
For example -
KK – Flops an Over Pair 67.3% of the time.
JJ – Flops an Over Pair 36.2% of the time.
88 – Flops an Over Pair 10.2% of the time.
Unpaired Holdings – Breakdown
Bottom Pair = 8.98%
Middle Pair = 10%
Top Pair = 10%
Once again, it heavily depends on the starting hand.
Odds with AKo
Bottom Pair = 0%
Middle Pair = 0%
Top Pair = 29%
Odds with 98o
Bottom Pair = 4.9%
Middle Pair = 15.6%
Top Pair = 8.45%
Odds with 32o
Bottom Pair = 26.9%
Middle Pair = 2.02%
Top Pair = 0%
It really should not come as a surprise that high-card hands are more likely to make top Pairs, mid-card hands are more likely to make Mid Pairs, and low-card hands are more likely to make bottom Pairs.
It’s actually impossible for AKo to flop a second or bottom Pair, think about it!