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Registration numbers must be at least 3 inches tall, in plain vertical block characters that contrast with the hull. Federal rule 33 CFR 173.27 sets that minimum and every state applies it — a few word it more strictly.
Reviewed August 22, 2026
33 CFR 173.27 requires the number to be painted or permanently attached to each side of the forward half of the vessel in plain vertical block characters not less than 3 inches in height. States adopt this minimum in their own boating law; none allow smaller characters.
Measure the characters themselves — cap height from the top of the digit to the baseline — not the vinyl sheet, the backing paper, or the transfer tape border. Our decals are cut so the characters measure a true 3 inches.
Yes. Three inches is a floor, not a ceiling. On a large hull, 4 to 5 inch characters read better from 100 feet and still satisfy every state. What is never allowed is condensing or shrinking characters to fit a tight space.
Most states repeat the federal phrasing. California's DMV language says characters must be more than three inches. When a state's own wording is stricter than the federal floor, follow the state.
Taken verbatim from each state's own agency material in our regulatory dataset.
| State | Published wording | Agency |
|---|---|---|
| California | More than 3 inches | California Department of Motor Vehicles |
| Texas | 3 inches | Texas Parks and Wildlife Department |
| Florida | 3 inches | Florida Highway Safety and Motor Vehicles |
| Michigan | 3 inches | Michigan Secretary of State / Michigan DNR |
| Wisconsin | 3 inches | Wisconsin Department of Natural Resources |
| Minnesota | 3 inches | Minnesota Department of Natural Resources |
| North Carolina | 3 inches | North Carolina Wildlife Resources Commission |
| South Carolina | 3 inches | South Carolina Department of Natural Resources |
| Georgia | 3 inches | Georgia Department of Natural Resources / Law Enforcement Division |
| Tennessee | 3 inches | Tennessee Wildlife Resources Agency |
Rules change. Confirm with your state agency before ordering, and see the full 48-state requirement guide.
No. Three inches is the minimum. Larger characters are legal and easier to read at distance.
It applies to vessels required to be numbered, which in most states includes any motorized vessel. Sailboats without mechanical propulsion are handled differently state by state.
No. Height is measured on the alphanumeric characters only.
The designer lays out a true 3-inch plain block set with correct spacing, cut from six-year marine vinyl and shipped ready to apply.
Editorial review date: August 22, 2026. We publish state-specific rules only where an official agency source confirms them.
