Although the size of a basketball court and other dimensions, such as the three-point line, vary from league to league, the distance of the free throw line to the hoop remains a consistent 15 feet at virtually every level. This measurement is taken from the plane of the front of the backboard. Because the front of the backboard runs parallel to the baseline, you can take your measurements from the baseline.
Place the start of your measuring tape on the baseline directly under the hoop. With your chalk, mark the baseline at this starting position.
Extend the measuring tape 15 feet away from the the baseline. Make sure you extend the measuring tape at a 90-degree angle from the baseline. With your chalk, mark this 15-foot point.
Return to the baseline. Measure 6 feet to the right and 6 feet to the left of the chalk mark along the baseline from step one. Mark these new points with chalk.
Extend your measuring tape at a 90-degree angle from one of these points on the baseline from step three. With your chalk, mark the 15-foot point.
Extend your measuring tape at a 90-degree angle from the other point on the baseline from step three. With your chalk, mark the 15-foot point.
Connect the three chalk marks that you made 15 feet away from the baseline. This forms your free-throw line.