We demonstrate numerical refocusing in coherent confocal laser scanning microscopy based on synthetic optical holography. In this physics-based approach, computational propagation is implemented on the complex signal recovered in synthetic holography, consistent with wave physics and the parameters of the microscope. An experimental demonstration is shown to restore an in-focus image of a test object from data acquired at several focal plane off-sets. Numerical refocusing can provide focused views on samples with large height variation, with a potential application in confocal optical surface profiling.