Protein Creatinine Ratio Calculator (UPCR, estimated 24-hour urine protein)

Understanding the protein creatinine ratio calculator — concept and principle

The urine protein-to-creatinine ratio (UPCR) estimates how much protein is lost in the urine per day from a single spot sample, without a 24-hour collection. Doctors use it to detect and monitor kidney disease and pre-eclampsia.

Spot urine ratio: with the default inputs the result is 400 mg/g (≈ 0.4 g/day · moderately raised).

How it is calculated

UPCR (mg/g) = urine protein (mg/dL) ÷ urine creatinine (mg/dL) × 1,000

mg/mmol = mg/g ÷ 8.84

Estimated protein per day (g/day) ≈ UPCR (mg/g) ÷ 1,000

Protein in g/L × 100 = mg/dL; creatinine in mmol/L × 11.312 = mg/dL.
Bands: under 150 mg/g normal to mildly increased, 150–500 moderately increased, over 500 severely increased; about 3,500 or more nephrotic range.

The principle

Urine concentration varies through the day, so a protein value alone can mislead. Creatinine is excreted at a fairly steady rate, about 1 g a day in an average adult. Dividing protein by creatinine cancels out how concentrated the urine is, and because daily creatinine is about 1 g, the ratio in mg/g is close to the grams of protein lost per day.

Worked example

Default inputs: urine protein 40 mg/dL, urine creatinine 100 mg/dL.

UPCR = 40 ÷ 100 × 1,000 = 400 mg/g → Moderately increased.
In mg/mmol = 400 ÷ 8.84 = 45.2.
Estimated protein ≈ 0.4 g/day.

Each point is the calculator re-run with only “Urine creatinine” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Urine creatinine	Protein/creatinine ratio (mg/g)
25	1,600
50	800
75	533
100	400
125	320
150	267
200	200

How to read the result

Where does your result fall?

Persistent proteinuria is a marker of kidney damage and a risk factor for kidney and heart disease. A single high value should be repeated, since exercise, fever, infection and standing can raise it temporarily. In pregnancy a UPCR of 30 mg/mmol (about 0.3 g/g) or more supports significant proteinuria in pre-eclampsia assessment.

Common mistakes

Mixing units between protein and creatinine.
Using it in people with very high or very low muscle mass, where daily creatinine differs from 1 g.
Confusing protein/creatinine with albumin/creatinine ratios.

Keep in mind: This is not a diagnosis. Protein in the urine should be evaluated by a doctor.

Frequently asked questions

What is a normal protein/creatinine ratio?

Under 150 mg/g (about 15 mg/mmol).

Is UPCR as good as a 24-hour urine?

It correlates well and is more convenient, though a 24-hour collection may still be used in some situations.

What is the difference from ACR?

ACR measures only albumin and is preferred for early kidney damage, especially in diabetes.

Sources: KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Int Suppl 2013;3(1):1–150 · NICE guideline NG133, Hypertension in pregnancy: diagnosis and management (2019)

Checked 9 Nov 2026. KDIGO 2012 CKD guideline, Kidney Int Suppl 2013;3(1) — albuminuria/proteinuria categories; PCR equivalents under 150, 150–500 and over 500 mg/g and the nephrotic range of about 3.5 g/day are standard values.

Your numbers