Automatic success/failure

[Rystil Arden]

How often can you roll a 20 on a d20?

Unless you prefer to use d100 as an attack roll... reduce the 5% (1-in-20) to 1% chance of a lucky strike.

A lot, actually. 5% of the time. And using 1d100 for an attack roll would break the entire system

 

[Ranger REG]

A lot, actually. 5% of the time.

Meh. I can accept a natural 20 at 5% of the time. Anything more and I will find the dice and roller suspicious.

 

[Falkus]

How often can you roll a 20 on a d20?

Not often enough when you're a player.

 

[Nonlethal Force]

How often can you roll a 20 on a d20?

Unless you prefer to use d100 as an attack roll... reduce the 5% (1-in-20) to 1% chance of a lucky strike.

Technically, only 1 out of 400 rolls. But that is assuming you have to roll the first 20. If the first 20 is a given, then yes it is 1 out of 20.

Essentially, it works like this. You sit down and roll a d20 twice. Now do that sequence 400 times. In all that span you should get one 20-20 roll. Statistiaclly speaking you will get 20 rolls with a 20 on the first die and 20 rolls with a 20 on the second die ... but only 1 out of 400 will it have a 20 be on both dice.

 

[Rystil Arden]

Technically, only 1 out of 400 rolls. But that is assuming you have to roll the first 20. If the first 20 is a given, then yes it is 1 out of 20.

Essentially, it works like this. You sit down and roll a d20 twice. Now do that sequence 400 times. In all that span you should get one 20-20 roll. Statistiaclly speaking you will get 20 rolls with a 20 on the first die and 20 rolls with a 20 on the second die ... but only 1 out of 400 will it have a 20 be on both dice.

No, he doesn't mean how many times will you get 2 20s, he means how many for the first 20. Because under the basic rules, that's all you need for an auto-hit.