Inch
The inch is the imperial unit of length with which many standard measurements in golf are defined.
The inch comes into play wherever historical measurements originate from the British rulebook. One inch equals 2.54 centimeters. The best-known measurement is the hole diameter: 4.25 inches, exactly 108 millimeters — uniform worldwide since 1891. Ball size is also defined via the inch: the ball must have a diameter of at least 1.68 inches, just under 43 millimeters. Anyone who has clubs measured also constantly comes across inches instead of centimeters in length specifications.
In practice you encounter this during club fitting and on the course. An example: your putter is cut to 34 inches because your posture requires it. Half an inch more or less noticeably changes your address position. Iron lengths and grip sizes are also given in inch steps. On the course itself, by contrast, you calculate in meters or yards, depending on the facility — the inch remains the measure of equipment and the hole.
A typical misconception is mixing it up with the yard. Both come from the same system but differ by a factor of 36. Anyone who habitually reads distance figures as inches quickly ends up in chaos. Remember just two numbers: the hole at 4.25 inches and the ball at 1.68 inches. All other measurements follow from these or from the rules around the cup in detail.
FAQ
Why are the hole and the golf ball defined in inches instead of centimeters?
Because these measurements originate from the British rulebook and were set historically. One inch equals 2.54 centimeters: the hole measures 4.25 inches, the ball must have a diameter of at least 1.68 inches. Both figures apply uniformly worldwide, the hole diameter since 1891.
Where exactly do I encounter the inch when buying clubs?
In almost all length and grip specifications: club lengths, grip sizes and adjustments are given in inch steps. An example: your putter is cut to 34 inches during fitting because your posture requires it — half an inch more or less noticeably changes your address position. On the course itself, by contrast, you calculate in meters or yards.
What is the difference between an inch and a yard?
Both units come from the same English system but differ by a factor of 36: one yard is 36 inches. In golf they split cleanly — the inch is the measure for equipment and the hole, the yard the measure for distances on the course. Anyone who habitually reads distance figures as inches quickly ends up in chaos.