Protein-Creatinine Ratio Calculator (UPCR)

The urine protein-to-creatinine ratio (UPCR, also called PCR) is the ratio of protein to creatinine measured in a single spot urine sample. Because both values come from the same sample, the urine concentration cancels out, so the ratio approximates the 24-hour protein excretion. A worked example: urine protein 120 mg/dL with urine creatinine 80 mg/dL gives 120/80 = 1.5 g/g, roughly 1.5 g of protein per day, or 1500 mg/g.

Divide the urine protein by the urine creatinine when both are in the same units: UPCR (g/g) = urine protein (mg/dL) / urine creatinine (mg/dL). Multiply by 1000 to get mg/g. For example, protein 120 mg/dL and creatinine 80 mg/dL gives 120/80 = 1.5 g/g = 1500 mg/g, with an estimated 24-hour excretion of about 1.5 g/day.

A UPCR below 0.2 g/g (200 mg/g) is generally considered normal, based on the classical Ginsberg criteria. For example, protein 30 mg/dL with creatinine 200 mg/dL gives 30/200 = 0.15 g/g = 150 mg/g, which falls in the normal range. KDIGO additionally classifies total protein/creatinine below 150 mg/g as A1 (normal to mildly increased).

A UPCR above 3.5 g/g is classified as nephrotic range, corresponding to an estimated excretion of more than 3.5 g of protein per day. For example, protein 450 mg/dL with creatinine 90 mg/dL gives 450/90 = 5.0 g/g = 5000 mg/g, which is nephrotic range. Nephrotic-range proteinuria generally warrants prompt nephrology evaluation.

Spot UPCR in g/g correlates closely with grams of protein excreted in 24 hours (Ginsberg et al., 1983). A UPCR of 1.5 g/g implies roughly 1.5 g/day, and a UPCR of 5.0 g/g implies roughly 5 g/day. This correlation works best when daily creatinine excretion is near 1 g; it is less accurate in very muscular or very small patients.

UPCR measures total urine protein relative to creatinine, while ACR (albumin-to-creatinine ratio) measures only albumin. ACR is preferred for early detection of diabetic kidney disease because albumin leaks first, while UPCR detects protein of any type, including non-albumin protein seen in tubular disease or multiple myeloma. For example, albumin 45 mg/dL with creatinine 90 mg/dL gives ACR = 500 mg/g, which is KDIGO category A3 (severely increased).

KDIGO classifies ACR as A1 below 30 mg/g (normal to mildly increased), A2 from 30 to 300 mg/g (moderately increased, microalbuminuria), and A3 above 300 mg/g (severely increased, macroalbuminuria). For example, albumin 9 mg/dL with creatinine 100 mg/dL gives 90 mg/g, which is category A2.

The UPCR assumes your daily creatinine excretion is about 1 g, which is not exact for everyone — muscular people excrete more, small or elderly people excrete less. Dilute urine (low creatinine) can inflate the ratio and concentrated urine can deflate it. The calculator flags urine creatinine below 50 mg/dL (dilute) or above 300 mg/dL (concentrated) so you can judge the context.

Yes. Transient proteinuria can follow vigorous exercise, fever, dehydration, or a urinary tract infection, and a random spot sample may not reflect your usual baseline. Guidelines recommend confirming persistent proteinuria with a repeat test, ideally a first-morning void, before drawing conclusions. Menstruation or contamination can also affect results.

An abnormal UPCR is a prompt to repeat the test and look at the bigger picture — blood pressure, serum creatinine, eGFR, and the clinical history — not a diagnosis by itself. Values in the nephrotic range (above 3.5 g/g) or a rising trend over time are reasons to consult a nephrologist. This calculator is for education and estimation only; all decisions about real patients belong with a qualified physician.