Under standard rugby league laws, the playing field between the two goal lines is 100 metres long.
That measurement describes the field of play itself, from one goal line to the other. It does not include the in-goal areas behind the goal lines, where tries are grounded and goal kicks may be taken. The full surface from dead-ball line to dead-ball line is therefore longer than 100 metres.
The field is generally 68 metres wide, although local ground conditions and competition regulations can affect exact markings. The halfway line divides the field into two 50-metre sections, and the 20-metre lines are important for restarts after the ball goes dead or is forced in-goal.
A common mix-up is to quote the total stadium playing surface rather than the distance between goal lines. Another is to confuse rugby league’s field dimensions with rugby union’s typical pitch measurements, which are governed by different laws.