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U.S. Coast Guard regulations and every state require boat registration numbers to be at least 3 inches tall, in plain vertical block characters, and clearly legible from at least 100 feet away.
The U.S. Coast Guard requires that registration numbers displayed on the bow of any motorized vessel be at least 3 inches in height. This rule applies to all states because federal law sets the minimum, and states adopt it or make it stricter.
Measure the height of the characters themselves — not the backing paper or the overall decal sheet. The 3-inch minimum applies to the numbers and letters, excluding any state name or validation sticker.
Yes. Making them taller is allowed and can improve visibility, especially on larger boats. The 3-inch mark is the minimum, not the recommended or maximum height.
No, 3 inches is the minimum required height. You can make them larger for better visibility.
It applies to motorized vessels. Sailboats without motors may have different marking requirements depending on the state.
No. The 3-inch rule applies to the alphanumeric characters. Separators and spaces are not measured.
Our designer enforces the 3-inch height, plain block font, and contrast rules automatically.
