Wheel Bolt Pattern (PCD) Calculator — 4, 5, 6 & 8 Lug
Find a wheel's bolt pattern from a tape measurement — the pitch circle diameter for 4-, 5-, 6- and 8-lug wheels from the distance between adjacent holes or, for 5-lug, from the centre of one hole to the far edge of the opposite hole — with mm ↔ inch conversion, common patterns (5×114.3, 5×120, 6×139.7) and the dual-pattern compatibility check.
How it works
PCD = adjacent centre-to-centre ÷ sin(180° ÷ lugs) · 4 lugs: × 1.414 · 5 lugs: × 1.701 · 6 lugs: × 2.0 · 8 lugs: × 2.613 · 5 lugs: PCD ≈ centre of one hole to the far edge of the second hole along · even lugs: PCD = opposite centre-to-centre
Lug holes are spaced evenly around a circle whose diameter is the bolt pattern, and on wheels with an even number of holes that diameter can be measured straight across between opposite holes. Odd counts have no opposite hole, so the pattern is recovered from the chord between neighbours through the geometry of the triangle they form with the centre — for five lugs the multiplier is 1.701 — or by the mechanic's trick of measuring from the centre of one hole to the far edge of the hole two positions along, which lands within a fraction of a millimetre of the diameter. Because several common patterns differ by less than a millimetre, the measurement must be taken carefully and the result matched to a known size rather than trusted raw.
Worked example
Two adjacent holes on a 5-lug wheel measure 67.2 mm centre to centre: 67.2 × 1.701 = 114.3 mm, so the wheel is 5×114.3 (5×4.5″). Its near neighbour 5×115 differs by only 0.7 mm — bolts would go in, but the wheel would sit off-centre — while 5×120 is clearly different at 70.5 mm between adjacent holes.
Frequently asked questions
Can I run 5×114.3 wheels on a 5×115 hub?
Not properly. The 0.7 mm mismatch loads the studs unevenly and the wheel can loosen or crack around the holes. Some aftermarket "wobble" bolts are engineered for that specific swap on some cars; otherwise, no.
How do I measure a 5-lug pattern with a tape?
Measure from the centre of one stud hole to the far edge of the second hole clockwise (skip one). That distance equals the PCD to within about 0.5 mm.
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