We report a comparison of laser power measurements at the {\text{F 2}}_{} -laser wavelength of 157\text{\hspace{0.17em} nm} made at two facilities of the Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute. At the PTB laboratory at the electron storage ring BESSY II in Berlin, the scale for laser power was directly traced to a cryogenic radiometer operating at 157\text{\hspace{0.17em} nm} , whereas at the PTB laser radiometry facility in Braunschweig the calibration of transfer detectors was performed with a newly developed standard for laser power at 157\text{\hspace{0.17em} nm} , which is traceable in several steps to a cryogenic radiometer operating at 633\text{\hspace{0.17em} nm} . The comparison was performed under vacuum conditions with laser pulse energies of \sim 10\text{\hspace{0.17em} μJ} , however with different average powers because different primary standard radiometers were used. The relative deviation for the responsivity of the transfer detector was 4.8\% and thus within the combined standard uncertainty.