Urine Albumin-to-Creatinine Ratio (UACR) Calculator
Calculate the urine albumin-to-creatinine ratio (UACR/ACR) in mg/mmol and mg/g from a spot urine sample and see the KDIGO albuminuria category (A1, A2 or A3).
How it works
UACR (mg/mmol) = urine albumin (mg/L) ÷ urine creatinine (mmol/L) · UACR (mg/g) = urine albumin (mg/L) ÷ urine creatinine (g/L) · 1 mg/mmol = 8.84 mg/g · creatinine mg/dL ÷ 11.312 = mmol/L
Albumin should barely appear in urine, and even small amounts are an early sign of kidney damage and a strong predictor of cardiovascular risk, especially in diabetes and hypertension. Dividing a spot urine albumin by urine creatinine cancels out how concentrated the urine is, and because adults excrete roughly 1 g of creatinine a day, the ratio in mg/g approximates albumin excretion in mg per day. KDIGO classifies albuminuria as A1 (below 3 mg/mmol or 30 mg/g), A2 (3–30 mg/mmol or 30–300 mg/g) and A3 (above 30 mg/mmol or 300 mg/g); together with the eGFR category it stages chronic kidney disease.
Worked example
A spot urine with albumin 60 mg/L and creatinine 8 mmol/L: UACR = 60 ÷ 8 = 7.5 mg/mmol, which is 60 ÷ (8 × 0.11312) = 66 mg/g — category A2, moderately increased albuminuria. It should be confirmed on 2 of 3 samples collected over 3–6 months.
Sources: KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD. Kidney Int 2024;105(4S):S117–S314 · National Kidney Foundation: Albumin-to-creatinine ratio (uACR)
Frequently asked questions
What is a normal urine albumin-to-creatinine ratio?
Below 3 mg/mmol (30 mg/g) — KDIGO category A1. Many labs flag a UACR of 2.5 mg/mmol or more in men and 3.5 mg/mmol or more in women as raised, because women excrete less creatinine.
How do I convert UACR from mg/mmol to mg/g?
Multiply by 8.84 (because 1 mmol of creatinine weighs 113.12 mg). For example 3 mg/mmol ≈ 27 mg/g and 30 mg/mmol ≈ 265 mg/g; KDIGO rounds the cut-offs to 3/30 mg/mmol and 30/300 mg/g.
Is microalbuminuria the same as A2?
Yes. KDIGO replaced “microalbuminuria” with “moderately increased albuminuria (A2)” and “macroalbuminuria” with “severely increased albuminuria (A3)”.
What can raise UACR temporarily?
Vigorous exercise in the previous 24 hours, fever, urinary tract infection, menstruation, very high blood pressure and high blood sugar can all raise it, which is why an abnormal result should be confirmed on 2 of 3 samples, ideally first-morning urine.
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Educational calculation only, not medical advice or a diagnosis. Reference ranges and units differ between laboratories; interpret any result with your doctor in the context of your full clinical picture.