Protein-Creatinine Ratio Calculator (Urine PCR)
Calculate the urine protein-to-creatinine ratio (PCR) from a single spot urine sample. PCR approximates 24-hour protein excretion and is used to screen for and monitor proteinuria without a timed collection.
mg/dL
mg/dL
Urine protein divided by urine creatinine (same sample)
- 1
Protein-Creatinine Ratio (mg/mg)
30 ÷ 100 = 0.3 - 2
PCR in mg/g creatinine
0.3 × 1000 = 300Multiplying by 1000 converts from mg/mg to mg per gram of creatinine — the form used in KDIGO guidelines.
How does this calculator work?
PCR (mg/mg) = urine protein (mg/dL) ÷ urine creatinine (mg/dL) from the same spot sample. Normal PCR is < 0.15 (< 150 mg/g); nephrotic range is > 3.5 (> 3500 mg/g). PCR numerically approximates 24-hour urinary protein excretion in grams per day.
Formula
How this is calculated
The protein-creatinine ratio (PCR) is calculated from a random urine sample by dividing the protein concentration (mg/dL) by the creatinine concentration (mg/dL). Because creatinine is excreted at a fairly constant rate throughout the day (reflecting muscle mass), using it as a denominator corrects for urine dilution. A PCR below 0.15 mg/mg (150 mg protein per gram of creatinine) is considered normal; values above 0.5 mg/mg suggest significant proteinuria; values above 3.5 mg/mg (3500 mg/g) fall in the nephrotic range.
The PCR in mg/mg is numerically equivalent to g/g and approximates the total protein excreted in grams per day, assuming daily creatinine excretion of about 1 g. The mg/g form (multiply PCR by 1000) is more commonly reported in clinical guidelines (e.g., KDIGO).
This calculator is for informational purposes. Actual 24-hour protein excretion varies with body muscle mass, diet and kidney function. Orthostatic (postural) proteinuria and false elevations from contamination (blood, vaginal secretion, semen) are not accounted for. Clinical interpretation should always involve a healthcare professional.
Frequently asked questions
A 24-hour collection requires precise timing and complete urine recovery over a full day, which is cumbersome and prone to collection errors. A spot PCR from a first-morning or random sample takes seconds and correlates well with 24-hour protein excretion in most patients, making it the preferred screening and monitoring test in clinical practice.
Nephrotic-range proteinuria is defined as PCR > 3.5 mg/mg (3500 mg/g creatinine), equivalent to approximately 3.5 g protein per day. This level of protein loss can cause hypoalbuminaemia, oedema and hyperlipidaemia. Diagnosis of nephrotic syndrome also requires confirming the clinical features alongside the laboratory result.
A first-morning midstream sample is preferred because it is most concentrated and avoids orthostatic proteinuria (protein that appears only when upright). Random samples are acceptable for monitoring established proteinuria. Samples taken immediately after exercise may show transient proteinuria and can give falsely elevated readings.
Also known as
TG we-Calculate Editorial Team. (2026). Protein-Creatinine Ratio Calculator (Urine PCR) [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/protein-cr-ratio-calculator
TG we-Calculate Editorial Team. "Protein-Creatinine Ratio Calculator (Urine PCR)." TG we-Calculate. 2026. https://we-calculate.com/calculator/protein-cr-ratio-calculator.
TG we-Calculate Editorial Team, "Protein-Creatinine Ratio Calculator (Urine PCR)," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/protein-cr-ratio-calculator
@misc{wecalculate_protein_cr_ratio_calculator, title = {Protein-Creatinine Ratio Calculator (Urine PCR)}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/protein-cr-ratio-calculator}}, year = {2026}, note = {TG we-Calculate} }
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