Symbol  Format  Data 

τ  Code Point 
U+03C4 
TeX 
\tau 

SVG 
The Greek small letter τ (tau) is used in math as the circle constant to represent a full rotation around a circle in radians. The value of is approximately and can be calculated by dividing any circle’s circumference by its radius. Typically, the symbol appears in an expression like this:
This expression is a formula for the area of a circle. In plain language, this expression can be read as: the area of the circle is equal to onehalf multiplied by the constant (tau) multiplied by the radius of the circle squared.
The capital Greek letter Τ (capital tau).
The circle constant τ (tau) is a geometric constant approximately equal to 6.283. The numeric value is defined as the length of any circle's circumference divided by the length of its radius.
Radians are a unit that measures angle using the radius of a circle. One radian is equal to the amount of rotation required to travel the length of one radius along the circumference of the circle.
The area of a circle is given by onehalf multiplied by τ (tau) multiplied by the radius of the circle squared.
The circumference of a circle is given the constant τ (tau) multiplied by the radius of the circle, where τ = 2π.