Albumin-to-Creatinine Ratio (ACR) Calculator

Health

The urine albumin-to-creatinine ratio (ACR) screens for early kidney damage by comparing albumin to creatinine in a urine sample. Enter your urine albumin and creatinine, and the calculator returns the ACR in mg/g with its category — normal, microalbuminuria or macroalbuminuria. A rising ACR is one of the earliest signs of kidney disease, especially in diabetes and high blood pressure.

Formula

ACR (mg/g) = Urine Albumin (mg/L) ÷ Urine Creatinine (g/L)
  • ACR (mg/g) = urine albumin (mg/L) ÷ urine creatinine (g/L).
  • Dividing by creatinine corrects for how dilute or concentrated the urine sample is.
  • Under 30 mg/g is normal (A1); 30-300 mg/g is microalbuminuria (A2); over 300 mg/g is macroalbuminuria (A3).
  • A random (spot) urine sample is usually enough; a first-morning sample is often preferred.
  • A single raised result should be confirmed with a repeat test before any conclusions are drawn.

Example Calculation

Inputs
  • Urine Albumin (mg/L): 15
  • Urine Creatinine (g/L): 1

With urine albumin of 15 mg/L and creatinine of 1 g/L, ACR = 15 ÷ 1 = 15 mg/g, which is within the normal (A1) range.

Frequently asked questions

What does the ACR test for?
It screens for albuminuria — small amounts of the protein albumin leaking into urine — an early marker of kidney damage.
Why divide albumin by creatinine?
Creatinine corrects for urine concentration, so a random sample gives a result comparable to a full 24-hour collection.
What is a normal ACR?
Below 30 mg/g is normal. 30-300 mg/g is microalbuminuria and above 300 mg/g is macroalbuminuria, both signalling kidney involvement.
Who should have this test?
People with diabetes or high blood pressure are screened regularly, as they are at higher risk of kidney disease.
Does one high result mean kidney disease?
Not on its own. Exercise, fever or infection can raise it temporarily, so a raised result is confirmed with repeat testing.