The definition of Angular Velocity used by these calculators may not be what you are used to. It is a distance over a time where that distance is curved. Not an angle over time as is commonly used. For more information please read Angular Velocity and Angular Momentum by Miles Mathis.
Calculate the angular velocity given the radius and tangential velocity.
Calculate the tangential velocity given the radius and angular velocity.
Calculate the radius given the tangential velocity and angular velocity.
The value of omega must be less than the velocity.