The mass distribution of stellar mass black holes can provide important clues to supernova modeling , but observationally it is still ill constrained . Therefore it is of importance to make black hole mass measurements as accurate as possible . The X-ray transient 1A 0620–00 is well studied , with a published black hole mass of 6.61 \pm 0.25 M _ { \sun } , based on an orbital inclination i of 51 \fdg 0 \pm 0 \fdg 9 . This was obtained by [ ] , as an average of independent fits to V - , I - and H -band light curves . In this work we perform an independent check on the value of i by re-analyzing existing YALO/SMARTS V - , I - and H -band photometry , using different modeling software and fitting strategy . Performing a fit to the three light curves simultaneously , we obtain a value for i of 54 \fdg 1 \pm 1 \fdg 1 , resulting in a black hole mass of 5.86 \pm 0.24 M _ { \sun } . Applying the same model to the light curves individually , we obtain 58 \fdg 2 \pm 1 \fdg 9 , 53 \fdg 6 \pm 1 \fdg 6 and 50 \fdg 5 \pm 2 \fdg 2 for V - , I - and H -band , respectively , where the differences in best-fitting i are caused by the contribution of the residual accretion disc light in the three diferent bands . We conclude that the mass determination of this black hole may still be subject to systematic effects exceeding the statistical uncertainty . Obtaining more accurate masses would be greatly helped by continuous phase-resolved spectroscopic observations simultaneous with photometry .