How to calculate internal volume of an object?

Using DSM to create a loudspeaker, it is vital to be able to calculate the internal volume of the speaker cabinet. This is an important parameter of such designs.

Is this possible?

Thanks for any tips destined for a newbie (please use a small spoon when explaining).

If this is not possible, would there be a way to export the drawing to an application offering this feature? Which?

Thanks beforehand!