U.S. License Plate Sizes and Dimensions

The standard passenger vehicle license plate size across the United States is 12 inches wide by 6 inches high, as regulated by the American Association of Motor Vehicle Administrators (AAMVA). This dimension is the standard in all 50 states and Washington, D.C.

Not all license plates in the United States are of the same size. Although passenger vehicle plate size is typically 12 inches wide by 6 inches high, some variations may apply for specialty plates, older plates, and collector vehicle plates. For instance, trailer plates and utility vehicles in some states may use different license plate sizes, while motorcycle plate sizes are different from the standard passenger vehicle license plate size. Also, temporary license plates issued for cars, trucks, buses, and trailers measure 11" x 6".

Nearly all states in the United States have their motorcycle license plate size as 4 inches high by 7 inches wide. Minnesota is the exception, as the state's motorcycle license plate size is 4.1875 inches high and 7.1875 inches wide.

6-Character Plates:

Common examples include the following format:

• ABC 123: Three letters followed by three numbers.
• 123 ABC: Three numbers followed by three letters.
• A12 B34: A mix of letters and numbers in a specific pattern.

7-Character Plates:

Some states use a 7-character format to accommodate more combinations. Examples of common license plate serials in this category include:

• ABC 1234: Three letters followed by four numbers.
• 1234 ABC: Four numbers followed by three letters.
• AB12 CD3: A mix of letters and numbers in a specific pattern.

Factors that determine plate number lengths include:

• Plate Type: Standard plates typically follow a fixed format set by the issuing jurisdiction, often containing six or seven characters. Vanity or custom plates, on the other hand, allow vehicle owners to select their own combinations within a set limit, which can result in shorter or longer sequences. Specialty plates, such as those issued for veterans, universities, or organizations, may include unique numbering formats, prefixes, or symbols that impact the overall character count.
• State Regulations: Another reason why license plate lengths may differ is the regulations that govern license plates in each state. Different states have their own rules regarding the minimum and maximum number of characters allowed. For example, while some jurisdictions may limit the number of characters to 6, others may allow more characters. These regulations are designed to maintain consistency and ensure that every vehicle has a unique identifier.
• Plate Format and Character Limitations: Some states employ specific letter-number combinations in a set format (such as "ABC-1234" or "123-XYZ"), and the design may dictate whether there are dashes, spaces, or special characters in between, affecting the total length. Additionally, different methods of plate creation, such as digital printing or embossed designs, may also impact the character count, especially if certain formatting styles are used.

Population density and registration volume can also influence the length of license plate numbers. In areas with higher populations and more vehicles on the road, there may be a need for longer license plate numbers to accommodate a greater volume of unique identifiers. In contrast, less populated regions may not need as many characters because there are fewer vehicles to register.

The standard size for license plate screws in the United States may vary depending on the vehicle's make and model. However, the most common size for license plate screws is 1/4-14-3/4 inch. This means the screw has a 1/4 inch diameter, 14 threads per inch, and is 3/4 inch long.

Note that some foreign vehicles, such as Honda, Toyota, and BMV, may use metric screws with a 6mm diameter, 1.0 thread pitch, and 16mm length. However, European vehicles may use smaller, finer-threaded screws, such as metric screws with 5mm diameter, 0.8 thread pitch, and 25mm length.

Some vehicles use bolts instead of screws to secure the license plate, especially those with pre-threaded metal inserts or specific mounting brackets. The size of bolts used for a license plate in the United States is generally the same as the size of screws. The standard bolt size for license plates is 1/4-inch diameter with a thread pitch of 14 (1/4-14). Hence, they are commonly referred to as 1/4-14 bolts.

In the United States, license plate sizes are mostly standardized, with the common dimensions being 12 inches wide by 6 inches high for passenger vehicles. However, there are some exceptions. Motorcycle plates are typically smaller, often measuring 7 inches by 4 inches. Similarly, specialty plates, such as those issued for historic vehicles, government use, or custom designs, may have unique dimensions or formatting. Also, older vehicles may have mounting brackets designed for non-standard plate sizes, which may require adapters or modifications for proper installation.

While most plates follow a consistent size for easy identification and compatibility with registration systems, consider checking state regulations or specific plate requirements before installation for good fitment.