Postvoid Residual (PVR): Urine that remains in the bladder, measured by a catheter or U/S, after the patient attempts to urinate. A PVR >200 ml suggests bladder obstruction or weakness.
Normal functional bladder capacity in adults ranges from approximately 300 to 400 ml. (IJCP 2011).
Normal bladder size: 300-400cc
At 120-130 cc, you start getting the urge to urinate.
References
Int J Clin Pract. 2011 Oct; 65(10): 1026–1036. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3206217/