Is there a caculation formula?
You need to post a link to the motor datasheet. Nema 23 just defines the size of the front face of the motor and the photo does not provide any data.
Also post a link to the stepper motor driver that you plan to use.
The maximum speed of a stepper motor will generally depend on the voltage at which it is driven and the load that it is expected to move. Other factors such as resonance at certain speeds, and whether you use microstepping can also affect the performance.
...R
RobotDiggMe:
Is there a caculation formula?
No, there isn't, because it depends on lots of factors like resonance, supply
voltage, winding inductance, microstepping.
In the "brake" situation, I think it is safe to assume that the final RPM will be zero.
This is the best stepper speed calculator I know: Stepper Motor Maximum Speed and Power Calculator
I should have mentioned: Check the datasheet for the motor.
But treat the torque/speed graphs there with caution, they don't account for resonanace effects
which are usually the limiting factor in any stepper-motor system.