The standard size for each foot is size 42, which is based on the French measurement centimeter, and all Iranian designers design and produce with this size.

To convert French centimeters to centimeters, use the formula: Foot size x 6.66 = height of the shoe insole For example: 42 x 6.66 = 279.72 This formula is correct if the insole size is standard and the shoe insole is not modeled (pointed insole).

The standardization of the back of the shoe, to avoid injury to the back of the foot, is based on the formula: Foot size x 6.66 = height of the insole ÷ 5 = height of the back of the shoe, which in sports shoes is considered to be under the overshoe if the back of the shoe is overshoe, for example: 42 x 6.66 = 279.72 ÷ 5 = 55.944 This number is calculated from the inside of the shoe (the thickness of the insole inside the shoe is deducted)

The standard width of the sole, or in other words, the width of the sole, is determined by the formula: Foot size x 6.66 = height of the insole ÷ 3 = standard width of the insole, which is the same in all models.

Standard width on the foot or in other words, the chest of the foot
Foot size x 6.66 = height of the insole ÷ 3 x 2 = chest size on the foot
In other words, if the height of your shoe insole is standard, the height of the shoe insole is equal to the circumference of the chest of your shoe insole.
For example, the height of the insole is 27.272 cm, the circumference of the chest of your shoe insole is also the same number.