Bolt Pattern Calculator

📋

Walk-through

How to Use This Calculator

3 steps

1

Measure your wheel's lug holes

Count the lug holes on the wheel or hub, then measure center-to-center between two holes: straight across for 4/6/8-lug patterns (any two opposite holes), or the farthest-apart pair for a 5-lug pattern (2 positions around the circle, not the nearest neighbor).

2

Enter the lug count and distance

On the PCD from Measurement tab, pick your lug count, choose mm or inches, and enter the measured distance. The bolt circle diameter (PCD) updates instantly.

3

Check the pattern match

The result card shows the closest common named pattern (like 5×114.3) if your measurement is within tolerance. Use the Common Pattern Reference tab to browse every listed pattern and confirm which vehicles typically use it.

⚡

Reference

Formula & Methodology

2 formulas

Even lug counts (4, 6, 8) — direct measurement

PCD = straight-across distance

An even number of evenly-spaced lugs always has a hole directly opposite another. The center-to-center distance between those two opposite holes IS the bolt circle diameter — no correction needed.

5-lug — chord correction

PCD = farthestHoleDistance ÷ sin(2 × 180° / 5) = farthestHoleDistance ÷ sin(72°) ≈ farthestHoleDistance × 1.0515

A 5-lug pattern has no opposite hole, so shops measure between the two farthest-apart holes (2 positions around the circle) instead of the nearest neighbor. For n points evenly spaced on a circle, a chord spanning m positions has length PCD × sin(m × 180°/n). Solving for PCD with n=5 and m=2 gives the well-known '×1.051' shop rule.

📖

Glossary

Key Terms Explained

7 terms

Bolt pattern The arrangement of a wheel's lug holes, described as lug-count × PCD (e.g. 5×114.3) — the number of bolts and the diameter of the circle their centers sit on.

PCD (Pitch Circle Diameter / bolt circle diameter) The diameter of the imaginary circle that passes through the center of every lug hole. Wheels only fit a hub if their PCD and lug count match (or use an adapter).

Lug count The number of wheel studs/bolts on the hub — most commonly 4, 5, 6, or 8 for passenger vehicles and light trucks.

Chord A straight line connecting two points on a circle. The measured lug-to-lug distance is a chord of the bolt circle; converting a chord back to the full circle's diameter requires trigonometry unless the chord happens to be a diameter itself (the opposite-hole case).

Straight-across measurement For an even lug count, the center-to-center distance between two holes directly opposite each other. This distance equals the PCD exactly, since it passes through the circle's center.

Farthest-hole (long) measurement For a 5-lug pattern, the center-to-center distance between the two holes that are farthest apart (skipping one hole between them). This is the standard 5-lug field measurement because there is no true opposite hole to measure straight across to.

Adjacent-hole measurement The distance between two immediately neighboring lug holes. This is a shorter chord than the farthest-hole measurement and requires a different (larger) multiplier — most 5-lug shop guides specifically call for the farthest-hole measurement instead, since it is less sensitive to small measurement error.

👥

Scenarios

Real-World Examples

3 worked examples

🚙

SUV owner replacing wheels

6-lug truck/SUV, straight-across measurement

Lug count 6-lug Measured distance 139.7 mm

Since 6 is even, the 139.7 mm straight-across measurement IS the PCD directly — no correction needed. This matches the common 6×139.7 pattern used on many Toyota, Chevrolet, and Ford trucks and SUVs.

🚗

Sedan owner shopping for aftermarket wheels

5-lug sedan, farthest-hole measurement

Lug count 5-lug Measured distance 109 mm (farthest-hole)

For 5 lugs, PCD = 109 × 1.0515 ≈ 114.6 mm — within tolerance of the common 5×114.3 pattern used by Toyota, Honda, Mazda, and most Ford trucks/SUVs. Note this measurement must be the farthest-apart pair of holes, not the nearest-neighbor pair, or the result will be wrong.

🔧

DIY mechanic double-checking a spare wheel

4-lug economy car, straight-across measurement

Lug count 4-lug Measured distance 100 mm

Since 4 is even, 100 mm straight across IS the PCD directly, matching the widespread 4×100 pattern found on many small Japanese and Korean cars — useful for confirming a spare or aftermarket wheel will bolt up before buying it.

📄

Deep Dive

Understanding the Bolt Pattern Calculator

3 chapters · 4 min read

A wheel's bolt pattern — its lug count and pitch circle diameter (PCD) — determines whether it will physically bolt onto a given hub. This calculator turns a simple tape-measure reading into an exact PCD, handling the tricky 5-lug case (which has no opposite hole to measure straight across) with the correct chord-to-diameter math, and matches your result against the most common patterns on the road.

How the Bolt Pattern Calculator works

For an even number of lugs (4, 6, 8), any two holes directly across from each other sit on a diameter of the bolt circle, so the straight-across measurement equals the PCD with no math required. A 5-lug pattern has no hole directly opposite another, so the standard field technique is to measure between the two farthest-apart holes (skipping one hole) and apply a trigonometric correction: PCD = measurement ÷ sin(72°) ≈ measurement × 1.0515. This is the same relationship used by wheel shops and bolt-circle gauges, derived from the geometry of a chord subtending a known angle on a circle of n evenly spaced points.

Inputs and what they mean

Lug count is the number of wheel studs on the hub — count them directly on the wheel or hub flange. Measured distance is a center-to-center measurement between lug holes, in millimeters or inches: straight across for 4/6/8-lug, or the farthest-apart pair for 5-lug. Getting the measurement technique right matters more than measurement precision — using the nearest-neighbor distance on a 5-lug wheel by mistake will produce a PCD far outside any real-world pattern.

Limits and edge cases

This calculator supports the four most common lug counts (4, 5, 6, 8) — some heavy-duty and specialty applications use other counts (like 10-lug on large trucks), which aren't covered here. The common-pattern match uses a small tolerance band to absorb minor measurement error, so a close-but-not-exact match still surfaces the likely pattern name; a measurement well outside tolerance for every listed pattern probably means a measurement or lug-count mistake rather than a genuinely uncommon pattern. Always confirm final fitment against the vehicle's owner's manual, door-jamb sticker, or a wheel-fitment database before purchasing wheels — some models span multiple bolt patterns across trims, years, or regional markets.

❓

Questions

Frequently Asked Questions

6 questions

What does the Bolt Pattern Calculator actually compute?+

It computes a wheel's bolt circle diameter (PCD) from your lug count and a single measured distance between lug holes, then matches that PCD against a table of common named bolt patterns (like 5×114.3) so you can identify or confirm your wheel's fitment.

Why is 5-lug measured differently from 4/6/8-lug?+

An even lug count always has a hole directly opposite another, so measuring straight across gives the PCD directly. A 5-lug pattern has no true opposite hole — the farthest any two holes get is 2 positions apart, which is 144° of arc as seen from the wheel's center. A trigonometric correction (using half that central angle, 72°) converts that farthest-hole chord measurement into the equivalent PCD.

Where does the '×1.051' multiplier for 5-lug come from?+

It comes from the chord formula for points evenly spaced on a circle: a chord spanning m positions out of n total has length PCD × sin(m × 180°/n). For a 5-lug pattern's farthest-hole pair, m=2 and n=5, so the angle is 72° and the multiplier is 1 ÷ sin(72°) ≈ 1.0515 — commonly rounded to 1.051 in shop references.

Why are 4, 6, and 8-lug patterns easier to measure?+

Because an even lug count always has two holes exactly 180° apart, the straight-across center-to-center distance between them passes directly through the circle's center — meaning it IS the diameter, with no trigonometry needed.

What does the Common Pattern Reference table show?+

It lists widely-used bolt patterns by lug count, their PCD in both millimeters and inches, and which vehicle makes/models commonly use each one — useful for sanity-checking a computed PCD or browsing patterns before you measure.

What units does the calculator expect, and how are metric/imperial names related?+

You can enter your measurement in millimeters or inches — the calculator converts internally and shows PCD in both. Bolt pattern names are usually written in whichever unit is conventional for that pattern's origin (e.g. 5×114.3 mm is the same physical pattern some older references call 5×4.5 in).

Download a one-page PDF of your numbers instantly. Add your email to also get our occasional calculator tips — no spam, unsubscribe anytime. Privacy.

Related Calculators