What size bolts hold a license plate?
In the United States, license plates are typically mounted with 1/4-14 UNC bolts, usually 1 inch to 1-1/2 inches long; in Europe and many other markets, metric screws such as M6 x 1.0 are standard, with lengths commonly from 12 mm to 25 mm. Exact sizes depend on the vehicle, bumper design, and whether a frame or spacer is used.
Beyond regional differences, the specific bolt size for your plate is determined by the plate thickness, mounting surface, and any spacers or frames in place. Always verify with your vehicle’s manual or the mounting hardware that came with your plate or frame before purchasing or installing.
Common license plate bolt sizes by region
Overview of typical sizes used in different regions and configurations.
- United States and Canada: 1/4-14 UNC bolts; common lengths range from 1 inch to 1-1/2 inches (25–38 mm), depending on plate thickness and bumper geometry; washers are usually used.
- Europe and many other markets: Metric screws, typically M6 x 1.0; common lengths range from about 12 mm to 25 mm to accommodate plate thickness and mounting spacers.
- Other configurations: Some vehicles or aftermarket frames may use alternative fasteners (for example, M5 x 0.8 or longer M8 variants) depending on the design; always verify with the manufacturer or mounting kit.
In short, regional standards cover the majority of installations, but always confirm the exact hardware for your car and mounting setup to avoid misfit or damage.
Choosing the correct length and installation basics
Guidance on measuring and selecting bolt length before installation.
- Measure the combined thickness of the license plate and any mounting frame or spacer, plus the bumper or mounting surface.
- Choose a bolt length that fully engages the mounting surface without protruding beyond the bumper or frame.
- Ensure the bolt head clears the plate/frame, uses a washer if recommended, and is compatible with corrosion-resistant materials (e.g., stainless steel).
- For US installations, use 1/4-14 UNC bolts; for EU/other markets, use M6 x 1.0 bolts, matching the measured thickness.
Using the correct length helps prevent plate rattling, damage, or loose mounting; tighten to the appropriate torque where specified and avoid cross-threading.
Practical installation notes
Some cars use studs or captive nuts instead of traditional bolts. In those cases, follow the vehicle’s instructions or use the provided mounting hardware to ensure a secure fit without damaging the bumper or plate.
Summary
License plate bolt sizes vary by region and vehicle. The most common configurations are 1/4-14 UNC bolts in North America and M6 x 1.0 metric screws in Europe, with lengths chosen to match plate thickness and mounting surface. Always verify the correct hardware from your vehicle’s manual or mounting kit, use appropriate washers, and torque to specification to keep the plate secure and undamaged.
