The bolt pattern calculator determines pitch circle diameter from a lug or stud measurement, helping identify wheel hub compatibility before getting replacement wheels and spacers.
Calculate Your Wheel’s True Bolt Pattern (PCD) From a Lug-to-Lug Measurement
This calculator turns a single stud-to-stud measurement into an exact wheel bolt pattern (PCD), so you can confirm hub-to-wheel compatibility before buying wheels, spacers, or hub adapters. Wheel and tire shops, home mechanics measuring an unbadged hub, and CNC machinists laying out custom adapter plates use it to skip manual trigonometry.
What to Measure on the Hub Before Running the Calculator
Select inches or millimeters, choose the lug count (3 to 12), and pick how you measured: center-to-center on adjacent studs, skip-one (for 5-lug hubs), or straight across on even lug counts. Enter that single distance. The calculator returns the true PCD plus a second measurement type so you can cross-check your reading against the hub itself.
How a Chord Measurement Converts to Pitch Circle Diameter
A bolt pattern is n evenly spaced studs sitting on a circle, so the straight-line (chord) distance between any two studs relates to the pitch circle diameter through basic circle trigonometry. This chord-to-diameter relationship is the same method used across CNC bolt-circle layout and automotive wheel-fitment references — it is not itself a single formula published by SAE, EPA, or ISO, and this page does not claim otherwise:
$$PCD = \frac{d}{\sin\left(\frac{k\pi}{n}\right)}$$
Here $d$ is your measured distance, $n$ is the lug count, and $k$ is 1 for adjacent studs, 2 for skip-one, or $n/2$ for straight across — valid only on even lug counts, where $\sin(\pi/2)=1$ makes the chord equal to the diameter directly, no trigonometry needed.
SAE J1982 does define the wheel and hub terminology (PCD, mounting pad, wheel disc) this calculator uses, but the arithmetic itself is geometry rather than a numbered SAE test procedure.
A less obvious consequence: on a 4-lug hub, Skip-One and Across Center land on the exact same pair of studs (skipping one stud on a 4-lug pattern puts you directly opposite), so this calculator hides the Skip-One option specifically for 4-lug patterns rather than offering a redundant, easily-confused input. The most common measuring mistake is reading stud-to-stud on the outside edges instead of true centers, which inflates the result by roughly one stud diameter.
Distance must be a positive, nonzero number; zero, blank, or negative entries return no result. Once converted to millimeters, results outside roughly 60–450 mm fall outside real passenger and light-truck hubs, so the calculator still computes the geometry but flags the output as an unlikely match rather than blocking it — useful for catching a wrong unit or a slipped decimal before you order parts.
Three Measuring Mistakes That Throw Off the Reading
Beyond edge-versus-center confusion, two other errors show up often:
- Selecting Across Center on an odd lug count (3- or 5-lug), where no stud sits directly opposite another — the calculator blocks this combination for exactly that reason.
- Switching the unit dropdown after typing the measurement instead of before, which converts a number that was already correct and throws off every downstream result.
- Rounding the raw measurement to a “nice” number before entering it, which can shift a 114.3 mm pattern to a false match with 115 mm or vice versa.
Where to Place Calipers for the Adjacent and Skip-One Readings
The diagram below shows a 5-lug hub. The solid chord is the Adjacent measurement (stud 1 to stud 2); the dashed chord is Skip-One (stud 1 to stud 3, skipping stud 2). Either measurement, entered with its matching method, resolves to the same PCD.
Common Factory Bolt Patterns This Calculator Will Recognize
These are widely documented factory patterns compiled from automotive wheel-fitment references, not sizes fixed by a single regulatory standard, so treat a match as a plausibility check rather than final confirmation:
| Lug Count × PCD (mm) | Inch Equivalent | Common On |
|---|---|---|
| 4 × 100 | 4 × 3.94″ | Honda, Toyota, Mazda, and Kia compact cars |
| 4 × 114.3 | 4 × 4.50″ | Nissan, Mitsubishi, Hyundai, and older Honda models |
| 5 × 100 | 5 × 3.94″ | Subaru, Toyota Corolla/Matrix, and Volkswagen |
| 5 × 114.3 | 5 × 4.50″ | Honda, Toyota, Mazda, Kia, and Hyundai |
| 5 × 120 | 5 × 4.72″ | BMW and Land Rover |
| 6 × 139.7 | 6 × 5.50″ | Toyota Tacoma/4Runner/Tundra, Chevrolet/GMC trucks, and Nissan Frontier |
| 8 × 170 | 8 × 6.69″ | Ford Super Duty F-250/F-350 |
A matching number doesn’t guarantee a safe fit — hub bore, wheel offset, and lug thread pitch all vary by trim and model year, so confirm the full spec against your vehicle before ordering wheels or adapters.
Bolt Pattern and PCD Questions From Wheel Shoppers
What is a bolt pattern or PCD?
Bolt pattern (also called PCD, or pitch circle diameter) describes the lug layout on a wheel hub: the stud count and the diameter of the circle passing through their centers, written as lug count × diameter, such as 5×114.3mm.
Can I use a tape measure instead of digital calipers?
On larger trucks a tape measure is usually close enough. On smaller cars the tolerance is tighter, so calipers cut the risk of being off by a millimeter or two, which is sometimes the difference between two similar patterns.
Why does the exact bolt pattern matter when buying wheels?
The lug holes have to line up with the studs on your hub. A wheel with the wrong pattern won’t bolt on regardless of size, offset, or brand, because stud spacing is fixed by the hub itself.
Do two vehicles with the same bolt pattern always share the same wheels?
Not necessarily. Matching bolt pattern is the first filter, but hub bore, wheel offset, and load rating also have to fit, so a numeric match alone doesn’t guarantee a correct or safe installation.
What if my measurement doesn’t match any listed pattern?
Re-measure center-to-center rather than edge-to-edge, and double-check the unit and method selected. If the result still falls between standard sizes, your hub may use a less common or regional pattern outside this reference list.