Bolt Pattern Calculator
Turn a tape-measure reading into a bolt circle diameter in mm and inches, and find the nearest standard pattern.
Enter your numbers and press Calculate.
The geometry
Bolt circle = measured distance ÷ sin(180° × k ÷ lugs), where k = 1 for neighboring studs and 2 when you skip one
Straight across on 4, 6 and 8 lugs, the distance is the bolt circle itself. Across one skipped stud on a 5-lug, the bolt circle is the distance × 1.051, which is where Gauge Magazine's 1.05 multiplier comes from.
| Metric | Inches | Neighbor studs (mm) |
|---|---|---|
| 4x100 | 4x3.94 | 70.7 |
| 4x108 | 4x4.25 | 76.4 |
| 4x114.3 | 4x4.50 | 80.8 |
| 5x100 | 5x3.94 | 58.8 |
| 5x108 | 5x4.25 | 63.5 |
| 5x112 | 5x4.41 | 65.8 |
| 5x114.3 | 5x4.50 | 67.2 |
| 5x120 | 5x4.72 | 70.5 |
| 5x127 | 5x5.00 | 74.6 |
| 5x135 | 5x5.31 | 79.4 |
| 5x139.7 | 5x5.50 | 82.1 |
| 6x114.3 | 6x4.50 | 57.1 |
| 6x135 | 6x5.31 | 67.5 |
| 6x139.7 | 6x5.50 | 69.8 |
| 8x165.1 | 8x6.50 | 63.2 |
| 8x170 | 8x6.69 | 65.1 |
Inches = mm ÷ 25.4. Neighboring-stud distance = bolt circle × sin(180° ÷ lugs).
What your tape should read
For 4, 6 and 8 lugs the first column is center to center straight across; for 5 lugs it is center to center across one skipped stud. The second column is the distance between neighboring studs, a handy cross-check on any pattern.
| Pattern | Main reading | Neighbor studs |
|---|---|---|
| 4x100 | 100.0 mm (3.94 in) | 70.7 mm (2.78 in) |
| 4x108 | 108.0 mm (4.25 in) | 76.4 mm (3.01 in) |
| 4x114.3 | 114.3 mm (4.50 in) | 80.8 mm (3.18 in) |
| 5x100 | 95.1 mm (3.74 in) | 58.8 mm (2.31 in) |
| 5x108 | 102.7 mm (4.04 in) | 63.5 mm (2.50 in) |
| 5x112 | 106.5 mm (4.19 in) | 65.8 mm (2.59 in) |
| 5x114.3 | 108.7 mm (4.28 in) | 67.2 mm (2.65 in) |
| 5x120 | 114.1 mm (4.49 in) | 70.5 mm (2.78 in) |
| 5x127 | 120.8 mm (4.76 in) | 74.6 mm (2.94 in) |
| 5x135 | 128.4 mm (5.05 in) | 79.4 mm (3.12 in) |
| 5x139.7 | 132.9 mm (5.23 in) | 82.1 mm (3.23 in) |
| 6x114.3 | 114.3 mm (4.50 in) | 57.1 mm (2.25 in) |
| 6x135 | 135.0 mm (5.31 in) | 67.5 mm (2.66 in) |
| 6x139.7 | 139.7 mm (5.50 in) | 69.8 mm (2.75 in) |
| 8x165.1 | 165.1 mm (6.50 in) | 63.2 mm (2.49 in) |
| 8x170 | 170.0 mm (6.69 in) | 65.1 mm (2.56 in) |
Computed from the bolt circle: straight across = PCD; skip one (5 lug) = PCD × sin 72°; neighbors = PCD × sin(180° ÷ lugs).
Before you buy wheels
- The stud count and bolt circle must match exactly; a wheel drilled a millimeter or two off will not seat properly on every stud.
- Check the center bore and the lug nut or bolt seat type along with the pattern.
- Use the size stamped on your current wheel rather than a tape reading when you can.
Sources
- https://tiregrades.com/tire-anatomy/wheels/how-to-measure-bolt-pattern
- https://www.cokertire.com/blog/measuring-wheel-bolt-pattern/
- https://store.gaugemagazine.com/blog/how-to-measure-a-bolt-pattern/
- https://drivenproducts.com/blogs/wheel-and-wheel-accessory-terminology/wheel-bolt-patterns-and-bolt-circles