Pot odds

You are facing a bet. Add what is already in the middle to what they just bet, then add your call on top: that is what you are playing for. Your call divided by that total is the share of the time you need to win for calling to break even.

This is the one calculation in poker with no judgement in it at all. Everything else on this page is an estimate. The price is a fact, it is available before you act, and most losing players never work it out.

Bet sizes repeat, so the prices they lay repeat too. Once those three are memorised, most decisions stop needing arithmetic at the table: you recognise the size, you know the number it demands, and all that is left is whether your hand clears it.

Bigger sizes move the number faster than people expect. An overbet of twice the pot is asking you to be right two times in five, which almost no drawing hand ever is. That is what an overbet is for.

Getting three to one means three parts already in the pot against one part from you, so four parts in total and one of them yours. One in four is twenty five percent, not a third. This single conversion error costs more money than any other piece of poker arithmetic.

Convert once, in whichever direction you find easier, and then stay there. Mixing the two mid-hand is how the mistake happens.