15 yards!
Many different reasons. Sometimes it's pass interference, offensive pass interference, roughing the kicker, roughing the passer, unnecessary roughness, horse callar tackle, encroachment, false start, illegal formation, intentional grounding, delay of game, tripping, block in the back, face mask, or holding. But there are many more.
A ten yard penalty. (1st and 10 to 1st and 20)
The penalty spot is 12 yards from the goal line.
In the NFL, the penalty is 15 yards. In college, the penalty is 10 yards.
15 yards and an automatic first down.
20
Football has changed by adding more rules to the game. The league is trying to cut down on the amount of injuries during the game so they put rules in affect to protect the players. For example, there used to not be a "roughing the passer" or "running into the kicker" penalty but too many injuries happened so they made rules against it.
Unnecessary roughness, unsportsmanlike conduct or delay of game may lead to a fifteen yard penalty in the NFL. There are two kinds, one is five yards and there is a fifteen yard one. But the NFL took out the five yard one in 2008.
The penalty is 15 yards if the referees think the face mask was grabbed intentionally and 5 yards if they think it was incidental.
In college football, the penalty is 15 yards. In the NFL, the penalty is 10 yards.
The penalty spot is typically 11 meters (12 yards) away from the goal line in soccer.