Urine Albumin-to-Creatinine Ratio Calculator
The Urine Albumin-to-Creatinine Ratio (UACR) Calculator divides urine albumin by urine creatinine to give a mg/g ratio that screens for kidney damage. It also reports the albuminuria category (A1, A2 or A3).
Rates and fees change frequently. Always confirm the current figures
with the official authority before relying on this result.
- Screening estimate. Persistent albuminuria requires physician confirmation.
Formula
ACR = urine albumin (mg/L) ÷ urine creatinine (g/L) = mg/g
- Dividing urine albumin (mg/L) by urine creatinine (g/L) gives the ratio directly in mg of albumin per gram of creatinine.
- Using creatinine corrects for how dilute or concentrated the urine sample is, so a single spot sample is reliable.
- Categories: A1 normal to mildly increased (under 30 mg/g), A2 moderately increased (30–300 mg/g), A3 severely increased (over 300 mg/g).
- This is a screening estimate; a diagnosis of persistent albuminuria needs repeat testing confirmed by a clinician.
Example Calculation
Inputs
- Urine albumin: 20 mg/L
- Urine creatinine: 1 g/L
With 20 mg/L of urine albumin and 1.0 g/L of urine creatinine: ACR = 20 ÷ 1.0 = 20 mg/g, which falls in category A1 (normal to mildly increased).
Frequently asked questions
What is the urine albumin-to-creatinine ratio?
It is urine albumin divided by urine creatinine, expressed in mg/g, used to screen for early kidney damage (albuminuria).
Why use creatinine instead of total volume?
Creatinine adjusts for urine concentration, so a single spot urine sample gives a result comparable to a 24-hour collection.
What do the categories mean?
A1 (under 30 mg/g) is normal to mildly increased, A2 (30–300 mg/g) is moderately increased, and A3 (over 300 mg/g) is severely increased albuminuria.
What causes a raised ACR?
Diabetes, high blood pressure and chronic kidney disease are common causes, though exercise, infection and fever can transiently raise it.
Is one high reading a diagnosis?
No. Persistent albuminuria usually requires two or three abnormal results over time, interpreted by a clinician.
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