Percentages

Hey what's the percentage to hit a one outer on the river?

The percentage of hitting a one outer on the river is approximately 2.17%.

So your sayin he still has a chance?

We all have seen 0.01% dry rivers flooding with water!

It’s 100% when you are playing against me lol

I saw in a few sources that you can calculate your chances as 2% per out, which will give you reasons to call or fold.

TBH I have no idea why there are many differents answers in the Net, the calculation seems simple: before the River you see 6 cards (yours 2 + 4 on the table). The deck is 52, so, there are 46 unseen cards remaining. The probability of hitting 1 out is 1/46 = approx. 2,18%

EDIT: Ok, I just found out. The above probability 2,18% is before showdown (so, before you have seen cards of any other players). After they have shown their cards (and you still do do not see your outer), the probability increases a bit, depending on how many players take part in the showdown and so, how many cards you see.

So, yes, it is definitely more than nothing. It just happens from time to time. Well about 2 times per 100 cases

I just checked a poker calculator by setting up a fictional scenario where a one-outer was the only win and it's about 2% as others have said. You could also just estimate more situations by estimating 50 cards in the deck (instead of 52) and 50 x 2 = 100 (percent), so each out is roughly 2%. It changes slightly for other variables like reverse-odds, but an estimate is usually good enough and so one out being 2% seems like a good backup if your mind goes blank, but you have an idea of your remaining outs.

1out * 2 = 2%

Simply put, when you're on the river, just multiply your outs by 2.
Ex: 1out on the river 1 x2 = 2%
When you're in Turner mode, just multiply by 4.