Measurement trap
There is no single official size for a football — only allowed ranges.
ranges, not one value
The rulebook allows a length of 11 to 11¼ inches, a long circumference of 28 to 28½ inches, a short circumference of 21 to 21¼ inches, and a weight of 14 to 15 ounces.
Standard range
Why this is interesting
You might expect the official ball of a professional league to have one exact size. The rules instead describe a window a ball has to fit inside.
How this measurement works
The NFL rulebook specifies the ball by ranges:
• Length (long axis): 11 to 11¼ inches • Long circumference: 28 to 28½ inches • Short circumference: 21 to 21¼ inches • Weight: 14 to 15 ounces
Any ball inside those limits conforms. None of them is “the” size.
How certain is this?
Standard range — permitted minimum and maximum values, not a single exact size.
Every figure is a permitted range from the rulebook; no midpoint is implied.
Sources & further reading
National Football League
Official Playing Rules of the National Football League(opens external site)
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