A goal is the moment the ball fully crosses the goal line between the posts and under the crossbar. Not half the ball. Not the ball touching the line. The entire ball must be over the line and inside the goal. That is why close calls make fans hold their breath: if even a tiny slice of the ball still sits on the grass outside the net, it is not a goal yet. Strikers can score with their foot, head, chest, or any legal body part except hands and arms. Once the referee confirms the ball crossed completely, the scoring team gets one point and play restarts from the center circle.
⚡ DID YOU KNOW?
The ball can hit the post, bounce on the line, and roll back out. If the whole ball never fully crosses the line, no goal is given. That is one reason goal line technology exists at the World Cup.