Post-Void Residual (PVR) Calculator
Enter the residual urine volume from a bladder scan (ultrasound or catheter) and the volume voided just before. The calculator shows the residual fraction, estimated total bladder capacity, and the standard clinical severity category.
mL
mL
Normal — bladder empties effectively
- 1
Estimated bladder capacity
40 + 300 = 340 - 2
Residual fraction
40 ÷ 340 × 100 = 11,8Percentage of estimated bladder capacity that remained after voiding.
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Post-void residual (PVR) is the urine left after voiding, measured by bladder scan or catheter. Less than 50 mL is normal; 50–100 mL borderline; 100–200 mL elevated; over 200 mL is significant retention. Residual fraction = PVR ÷ (PVR + voided volume) × 100. Always confirm with a clinician.
Formula
How this is calculated
Post-void residual (PVR) measures how much urine remains in the bladder after a person voids. It is commonly measured non-invasively by bladder ultrasound (a "bladder scan") within a few minutes of urination, or precisely by straight catheterisation. The volume voided is recorded from the same void to allow a residual fraction to be calculated.
The calculator estimates total functional bladder capacity as the sum of the voided volume and the residual, then expresses the PVR as a percentage of that capacity. The widely cited clinical thresholds are: under 50 mL normal; 50–100 mL borderline (a repeat measurement is usually recommended); 100–200 mL elevated (further evaluation is warranted); above 200 mL significant retention requiring prompt clinical attention.
These thresholds are general guidelines used in urology and continence practice — the 2020 AUA/SUFU guidelines, for example, cite 300 mL as a red-flag level. Clinical context matters: a single elevated reading may reflect anxiety, recent catheterisation, or diuretics. Two consistently elevated measurements are more clinically significant. Always confirm the interpretation with a qualified clinician.
Pogosta vprašanja
A PVR below 50 mL is generally considered normal. Values between 50 and 100 mL are borderline and often warrant a repeat scan; above 100 mL is considered elevated and above 200 mL is clinically significant retention requiring evaluation.
The most common method is a portable ultrasound bladder scanner, which is non-invasive and can be done at the bedside. For greater accuracy, the residual can be measured by inserting a catheter immediately after voiding and draining the remaining urine.
Yes. PVR can vary considerably depending on fluid intake, position, anxiety, medications (especially anticholinergics or alpha-blockers), and time since last void. Clinical guidelines generally recommend two or more consistent readings before diagnosing chronic urinary retention.
Znano tudi kot
TG we-Calculate Editorial Team. (2026). Post-Void Residual (PVR) Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/sl/calculator/pvr-calculator
TG we-Calculate Editorial Team. "Post-Void Residual (PVR) Calculator." TG we-Calculate. 2026. https://we-calculate.com/sl/calculator/pvr-calculator.
TG we-Calculate Editorial Team, "Post-Void Residual (PVR) Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/sl/calculator/pvr-calculator
@misc{wecalculate_pvr_calculator, title = {Post-Void Residual (PVR) Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/sl/calculator/pvr-calculator}}, year = {2026}, note = {TG we-Calculate} }
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