SPR (Stack-to-Pot Ratio)
Stack-to-pot ratio: the effective stack divided by the pot — a quick measure of how committed you are.
SPR is computed on the flop: the smallest remaining stack divided by the pot. Effective stacks of $100 and a $20 pot give you SPR 5. The number answers the most expensive question in no-limit hold'em — "am I committed with this hand?" — before the money goes in rather than after.
The working guidelines: at SPR 3 or below, top pair with a good kicker is a stack-off hand; the pot is big enough relative to what's left that folding is worse than gambling. Between 3 and 6 is a grey zone where kicker and board texture decide. At SPR 10 or above — deep stacks, small preflop action — one pair is a bluff-catcher, and playing for stacks requires sets, straights, flushes, or a draw strong enough to force with.
You control SPR before the flop whether you know it or not. A single-raised pot at $1/$2 with $200 stacks leaves roughly $190 behind and a $15 pot — SPR around 13, a speculative-hand environment where implied odds rule. A 3-bet pot with $100 stacks leaves $70 behind and a $30 pot — SPR barely above 2, a top-pair environment. Straddles and multiway limped pots also crush SPR, which is why small pairs lose value in wild games: the implied odds that justify playing them shrink with the effective depth.
Most low-stakes players never compute SPR and routinely stack off with one pair at SPR 12 — that's not bad luck, it's a structural misunderstanding of what the hand is worth. Check the number before every flop decision; it takes two seconds and pairs naturally with pot odds and implied odds to complete the picture. When genuinely in doubt, folding is rarely a disaster.