I think it is

AI told me

The size of the football used in flag football and the official NFL football also differs:

### NFL Football

- **Size**: The official NFL football is a regulation size, measuring about 28 centimeters (11 inches) in length and approximately 56 centimeters (22 inches) in circumference at the center. It weighs about 410 to 425 grams (14 to 15 ounces).

### Flag Football

- **Size**: The size of the football used in flag football can vary depending on the league and age group. Generally, it is smaller than the NFL ball. For youth leagues, the ball may be around 25 to 27 centimeters (10 to 10.5 inches) in length and lighter, weighing about 300 to 400 grams (10.5 to 14 ounces). Adult flag football leagues may use a ball closer to the size of a regulation NFL ball, but it can still be slightly smaller.

In summary, while the NFL football is standardized in size and weight, flag footballs can vary significantly based on the age and skill level of the players.