Jersey Number Rules: Which Numbers Are Legal at Each Level of Basketball

Number rules are not one rulebook but three, and they do not agree. The numbers a player can wear in international basketball, in United States college and in United States high school are three different lists, and the same jersey can be entirely legal at one level and rejected at another. International basketball allows every number from 1 to 99 plus both 0 and 00. United States college basketball opened the same way in 2023. United States high school basketball did not: the digits 6, 7, 8 and 9 are simply not on the permitted list, which means a number 8 jersey can be entirely legal for an adult and entirely illegal for a twelve-year-old. Below are the three rulebooks side by side, the measurements that travel with them, and what a scan of our own catalogue turned up.

This matters because a name-and-number jersey bought as a gift or for a youth team is usually judged against the strictest rulebook on the shelf, not the most permissive one.

Basketball's governing bodies do not share a single uniform code, so there is no one worldwide list of legal numbers. Each writes its own, and each revises it on its own timetable. The three below are the ones that decide what you can put on a jersey you order for yourself or for a child.

Both United States rulebooks also fix the nameplate. The name sits above the back number and has to clear it by at least an inch at every point; when the name is arched, the first and last letters must fall on the same horizontal plane. Decorative marks are allowed only above the number, and in college there may be no other letters or numbers at all between the name and the number. Both books also require the shirt to be tucked into the shorts.

The rulebooks are written in two different measurement systems, which is where a lot of avoidable mistakes come from. An order that asks for a 15 cm back number does not satisfy a 16 cm requirement, and a 6 inch back number is 15.24 cm, which clears 15 cm but not 16 cm. If a garment is being made for international competition, the safe reading is to work to the larger figure rather than the smaller one.

The names carry their own measurement, and it is the one most often overlooked. On the back of the garment the surname has to sit above the number with a gap of at least one inch between any point of a letter and any point of a digit, which is why a name set in a shallow arch with tall letters can crowd the number underneath it. The photo below is the same layout in a sewn build, where every letter is its own layer of thread and therefore sits slightly proud of the fabric.

We scanned every listing in the store, 4,969 of them, and read the number out of each product title. 578 listings carry a player number. Between them they use 42 different numbers, and the distribution is not random.

So 470 of the 578 numbered listings, about 81 percent, use a number a scholastic program would accept, and 108 use one it would not. The eleven numbers in that last group are not obscure either. Eight is one of the most requested numbers in basketball, and 24 listings in our range carry it. Three, one and two sit at the top of the count, which tracks how often those numbers come up in the modern game. The gap is not a mistake in our catalogue; it is a reminder that the number on an adult's jersey is drawn from a much wider pool than the one a child's jersey can use.

The practical question is rarely which rulebook is correct. It is which one the jersey will be judged against. In most cases that is obvious once you name the wearer, and the table below turns it into four routes.

• 1Assuming every level accepts 0 through 99. The international and college codes do; the scholastic code in the United States does not, and it is the one that decides most youth orders.
• 2Ordering 0 and 00 for two players on the same team. Both codes in the United States prohibit carrying the two together on one roster, even though each number on its own is permitted.
• 3Measuring the digit and forgetting the border. The width requirement applies to the digit itself, and the border is capped separately, so an oversized outline cannot be used to claim the digit is wide enough.
• 4Putting the name too close to the number. The one-inch clearance applies to every point of every letter, and a shallow arch with tall block lettering eats into that gap faster than it looks like it will.
• 5Expecting a mid-season change of number. In professional basketball a player normally keeps the number they started with, and a change usually follows a trade rather than a decision.

None of these are expensive problems if you catch them on the order form. All of them become expensive when a finished garment is sitting in a box that cannot be used on the day it was bought for.

Frequently Asked Questions

Five questions that come up when a number has to work in more than one league at once.