Albumin Creatinine Ratio (ACR) Calculator

Calculate urine Albumin-to-Creatinine Ratio (ACR) from a spot urine sample and classify albuminuria severity per KDIGO categories — with instant interpretation.

Enter urine values

Use a first-morning or random spot urine sample. Tap the unit badge on Creatinine to switch mg/dL ⇆ mmol/L.

Urine Albumin

Switch to mg/dL if your lab reports albumin that way.

Urine Creatinine

Albumin-Creatinine Ratio

– mg/g

–

A1 Normal A2 Moderate A3 Severe

Scale capped for display at 500 mg/g. A single elevated result should be confirmed on a repeat sample before diagnosing persistent albuminuria.

KDIGO Albuminuria Categories

A1 — Normal to Mildly Increased

<30 mg/g

(<3 mg/mmol)

Normal / physiological range

A2 — Moderately Increased

30–300 mg/g

(3–30 mg/mmol)

Formerly "microalbuminuria"

A3 — Severely Increased

>300 mg/g

(>30 mg/mmol)

Formerly "macroalbuminuria"

Formula

ACR (mg/mmol) = Urine Albumin (mg/L) ÷ Urine Creatinine (mmol/L) ACR (mg/g) = ACR (mg/mmol) × 8.84

About the Albumin-Creatinine Ratio

The urine ACR uses a spot urine sample to estimate 24-hour albumin excretion without the inconvenience of a timed collection. Dividing urine albumin by urine creatinine corrects for variation in urine concentration between samples, making a random spot sample almost as reliable as a 24-hour collection for most clinical purposes.

Clinical significance

ACR is a core component of KDIGO chronic kidney disease (CKD) staging, combined with eGFR to assess CKD risk category
Elevated albuminuria is an early, sensitive marker of diabetic and hypertensive kidney damage, often preceding a fall in eGFR
Persistent albuminuria (confirmed on 2 of 3 samples over 3–6 months) is more clinically significant than a single elevated value
Higher ACR is independently associated with increased cardiovascular risk, not just renal risk

Causes of transient (non-pathological) elevation

Vigorous exercise in the preceding 24 hours
Urinary tract infection or fever
Uncontrolled hyperglycemia or marked hypertension at time of sampling
Menstruation or heavy vaginal discharge contaminating the sample
Heart failure decompensation

Best practice for sample collection

A first-morning void is preferred; random spot samples are acceptable if first-morning isn't practical
Avoid testing during acute illness, heavy exercise, or menstruation where possible
A confirmed elevated ACR should prompt evaluation of eGFR, blood pressure, and glycemic control as part of a full CKD workup