Calculating the distance of a six in a cricket match is a combination of estimation and technology. While it's not an exact science, there are methods used to provide a reasonable estimate of the distance the ball has traveled when a batsman hits a six.

1. On-field Umpire's Estimation: In traditional cricket matches, particularly in Test cricket and some One Day Internationals (ODIs), the on-field umpire often relies on their experience to estimate the distance of a six. They visually track the trajectory of the ball as it clears the boundary and lands in the stands or beyond. The umpire then provides their best judgment regarding the distance. However, this method is not highly accurate and can vary depending on the umpire's perspective.

2. Stadium Infrastructure: Many modern cricket stadiums are equipped with infrastructure to help estimate the distance of sixes more accurately. This includes cameras placed strategically around the ground. These cameras capture the flight path and landing point of the ball, allowing for a more precise calculation of the distance. This technology is often used in limited-overs matches, such as T20 and ODIs.

3. Hawk-Eye Technology: Hawk-Eye, a sophisticated ball-tracking technology, is sometimes used to measure the distance of sixes. Hawk-Eye uses multiple cameras placed around the stadium to track the ball's movement. It creates a three-dimensional trajectory of the ball and calculates the distance it has traveled. Hawk-Eye technology is highly accurate and is used in various cricketing decisions, including LBW (leg before wicket) and reviewing close calls.

4. Manual Measurement: In some cases, especially when technology is not readily available, the distance of a six may be measured manually. Ground staff or officials use measuring tapes or other distance-measuring tools to determine the distance from the boundary to where the ball landed.

5. Fans and Spectators: Occasionally, fans and spectators in the stands or outfield may use their own estimates and markers, such as flags or banners, to indicate where a six has landed. While not official, these estimations can add to the excitement and atmosphere of a cricket match.

It's important to note that while these methods can provide reasonably accurate estimations, they are still subject to some degree of error and can vary from one measurement to another. The use of technology like Hawk-Eye has significantly improved the precision of distance calculations in modern cricket, ensuring that spectacular shots, like sixes, are appropriately acknowledged and celebrated.