Measure it, decode it, convert it — PCD in mm and inches
Offset = (backspace − width ÷ 2) × 25.4. Positive pushes the mounting face outboard; negative tucks the wheel in.
| Pattern | Inches | Commonly seen on (pattern-level, verify before buying) |
|---|---|---|
| 3-lug | ||
| 3x112.5 | 4.429" | smart fortwo; some classic microcars |
| 3x120 | 4.724" | Rare — some older/import microcars |
| 4-lug | ||
| 4x98 | 3.858" | Older Fiat, Lancia, Alfa Romeo compacts |
| 4x100 | 3.937" | Widely used older Japanese & Korean compacts |
| 4x108 | 4.252" | Various older Ford and European models |
| 4x110 | 4.331" | Common ATV/quad bolt circle |
| 4x114.3 | 4.5" | Older Japanese mid-size sedans |
| 5-lug | ||
| 5x98 | 3.858" | Some Fiat and Alfa Romeo models |
| 5x100 | 3.937" | Subaru, various Toyota & VW applications |
| 5x105 | 4.134" | Some GM compact cars |
| 5x108 | 4.252" | Various Volvo and Ford models |
| 5x110 | 4.331" | Various GM and Chrysler compacts |
| 5x112 | 4.409" | Many Mercedes-Benz, Audi, VW models |
| 5x114.3 | 4.5" | The most common Japanese/Korean 5-lug circle |
| 5x115 | 4.528" | Many GM crossovers and sedans |
| 5x118 | 4.646" | Some Mercedes-Benz vans |
| 5x120 | 4.724" | BMW family and various GM performance cars |
| 5x120.65 | 4.75" | Long-running GM 5-lug circle |
| 5x127 | 5.0" | Many Jeep, Dodge, Chrysler models (5x5) |
| 5x130 | 5.118" | Porsche cars and some vans |
| 5x132 | 5.197" | Some commercial vans |
| 5x135 | 5.315" | Older Ford trucks & SUVs (97-03 F-150 era) |
| 5x139.7 | 5.5" | Toyota/Lexus trucks & SUVs; older domestic trucks (5x5.5) |
| 5x150 | 5.906" | Toyota Tundra / Land Cruiser (2007+) |
| 5x155 | 6.102" | Some trailer axles |
| 5x160 | 6.299" | Some heavy-duty vans |
| 5x165.1 | 6.5" | Older domestic HD trucks (5x6.5) |
| 5x205 | 8.071" | Classic VW and common trailer axle circle |
| 6-lug | ||
| 6x114.3 | 4.5" | Many Nissan, Isuzu, older Toyota trucks |
| 6x127 | 5.0" | Various GM trucks & SUVs |
| 6x132 | 5.197" | Some commercial applications |
| 6x135 | 5.315" | Modern Ford F-150 (2004+) |
| 6x139.7 | 5.5" | The dominant Toyota/Nissan/GM truck circle (6x5.5) |
| 6x170 | 6.693" | Ford Super Duty trucks |
| 8-lug | ||
| 8x165.1 | 6.5" | Classic domestic HD truck circle (8x6.5) |
| 8x170 | 6.693" | Ford Super Duty (1999+) |
| 8x180 | 7.087" | Newer GM & Ram HD trucks |
| 8x200 | 7.874" | Some medium-duty trucks |
| 8x210 | 8.268" | Heavy-duty / medium-duty trucks |
This is a pattern-level reference, not a vehicle fitment database — same bolt pattern does not mean same fit (center bore, offset, width, and lug seat type all matter). Confirm against your owner's manual or door-jamb sticker before buying wheels.
| Studs | Adjacent angle | Divide by | Or multiply by |
|---|---|---|---|
| 3 lug | 120° | sin 60° = 0.8660 | 1.1547 |
| 4 lug | 90° | sin 45° = 0.7071 | 1.4142 |
| 5 lug | 72° | sin 36° = 0.5878 | 1.7013 |
| 6 lug | 60° | sin 30° = 0.5000 | 2.0000 |
| 8 lug | 45° | sin 22.5° = 0.3827 | 2.6131 |
The adjacent-stud factor works for even counts too — it's just easier to measure straight across when opposite studs exist.
A bolt pattern has two parts: how many studs, and the diameter of the circle they sit on — the pitch circle diameter, or PCD. "5x114.3" means five studs on a 114.3mm circle. The trick in the whole exercise is measuring that circle on an odd stud count, where no two studs sit across from each other.
For any stud count n, the distance between two adjacent stud centers is PCD × sin(180°/n). Flip it around and PCD = adjacent spacing ÷ sin(180°/n). For 5-lug that's spacing ÷ sin 36° = spacing × 1.7013; for 6-lug it's a clean ×2. Even counts (4, 6, 8) also let you measure straight across opposing studs, which equals the PCD with no math at all. The converter handles 25.4mm per inch both ways, and the matcher finds the nearest standard pattern, flagging anything more than 0.4mm off so close pairs like 120 vs 120.65 get a second look.
Count the studs, then measure center-to-center from one stud to an adjacent one with calipers if you have them — a tape measure's ±1mm matters at these scales. Pick your measurement mode, type the number, and read the pattern in both units plus its nearest standard. The backspace-to-offset converter handles the other half of wheel fitment math: offset = (backspace − width ÷ 2) × 25.4.
You count 5 studs and measure 67.2mm between two adjacent centers. PCD = 67.2 ÷ sin 36° = 67.2 × 1.7013 = 114.3mm, which is 114.3 ÷ 25.4 = exactly 4.5 inches. Pattern: 5x114.3 (5x4.5) — a direct standard match. Swap in 82.1mm adjacent on another hub and you get 82.1 × 1.7013 = 139.7mm = 5.5" — the 5x139.7 (5x5.5) truck pattern. On a 4-lug hub you'd skip the trig entirely: 100mm straight across opposite studs is 4x100, no conversion needed.
And the offset example: an 8-inch-wide wheel with 5.5" of backspace has offset = (5.5 − 8 ÷ 2) × 25.4 = 1.5 × 25.4 = +38.1mm — a common positive offset on modern sedans and crossovers. Every number above is one multiplication you can check by hand.
You can't measure straight across on an odd count, because no two studs sit opposite each other. Measure center-to-center between two adjacent studs, then divide by sin(36°) — equivalently, multiply by 1.7013. A 67.2mm adjacent spacing works out to 114.3mm, the classic 5x114.3 (5x4.5) pattern.
4.5 inches — 114.3 divided by 25.4 is exactly 4.5, which is why 5x114.3 and 5x4.5 are the same pattern written two ways. It's one of the most common 5-lug patterns on Japanese and Korean sedans and crossovers.
Yes. 5x4.5 inches × 25.4 mm/inch = 114.3mm. The decimal-inch and metric names describe one bolt circle. Similarly 5x5 = 5x127, 5x5.5 = 5x139.7, 5x4.75 = 5x120.65, and 8x6.5 = 8x165.1.
Even stud counts have opposite studs, so measure center-to-center straight across two opposing studs — that distance is the bolt circle diameter directly. For 4x100 you'll read about 100mm across. You can also use the adjacent-stud method: for 4-lug multiply the adjacent spacing by 1.4142, for 6-lug by exactly 2, for 8-lug by 2.6131.
No. A matching bolt pattern only means the studs line up. Fitment also depends on center bore diameter (hub-centric wheels need the right bore or a ring), offset (how far the mounting face sits from the wheel centerline), width, and the seat type of the lug hardware — conical, ball, or flat. Always verify against the owner's manual or the sticker on the driver's door jamb before buying.
They are different, barely: 120.65mm is 4.75 inches, a pattern long used on GM vehicles, while 120mm is the BMW-family circle. The 0.65mm gap is less than the tolerance of a careless tape measurement, which is why close patterns like these get mixed up — measure carefully and check the manual when you land between standards.