Bolt Pattern Measurement Calculator
On 4, 6 and 8-lug hubs the pattern is simply the distance between opposite studs. On 5-lug hubs there is no opposite stud, so you measure differently and convert. This tool does the conversion and tells you which standard pattern you have — or when the measurement can't decide.
A tape measure is good to about ±1 mm. Some standard
patterns are closer together than that — 5x114.3 vs 5x115, 5x120 vs 5x120.65 — and
they are not interchangeable. When the tool shows two candidates,
confirm with the vehicle lookup, not by eye.
The three methods
- Adjacent studs (any lug count): center of one stud to center of the next. PCD = distance ÷ sin(180° ÷ lugs). For 5 lugs that is ×1.7013; for 6, ×2; for 4, ×1.414.
- Skip-one (5-lug shop method): from the far outer edge of one stud to the center of the stud two positions away. Old rule says that equals the PCD; it's actually off by a millimetre or two, which is enough to confuse 114.3 with 115 — this tool corrects for stud diameter.
- Opposite studs (4, 6, 8 lugs): center to center straight across. That is the PCD, no math.