UACR Calculator
Get your urine albumin-to-creatinine ratio (UACR) in mg/g from a spot urine sample. Enter urine albumin (mg/dL or mg/L) and urine creatinine (mg/dL) to see the ratio and its KDIGO albuminuria stage.
Example: with Urine albumin 5 · Albumin unit mg/dL · Urine creatinine (mg/dL) 100 → Albumin-to-creatinine ratio: 50.0 mg/g.
- KDIGO albuminuria stageA2 — moderately increased, formerly microalbuminuria (30–300 mg/g)
- In SI units5.7 mg/mmol
Computed by the calculator below using its default values. Change any input to see your own numbers.
UACR (mg/g) = urine albumin (mg/dL) ÷ urine creatinine (mg/dL) × 1000. KDIGO stages: A1 <30, A2 30–300, A3 >300 mg/g.
Why the ratio beats a raw albumin number
Spot urine is diluted differently every time you go — drink a lot and everything is watered down, get dehydrated and it concentrates. A raw urine albumin reading swings with that dilution and is hard to trust. Dividing albumin by creatinine cancels most of the effect, because creatinine is produced and excreted at a fairly steady rate. The result approximates how much albumin leaks over a full day without needing a 24-hour collection.
Expressed as milligrams of albumin per gram of creatinine, the ratio slots into the KDIGO staging that pairs with eGFR. Albuminuria is one of the earliest signs of diabetic and hypertensive kidney damage, often appearing before filtration drops.
How it’s calculated
UACR (mg/g) = urine albumin ÷ urine creatinine × 1000, with both in mg/dL (albumin entered in mg/L is divided by 10 first). SI conversion: mg/g ÷ 8.8402 = mg/mmol. KDIGO categories: A1 <30, A2 30–300, A3 >300 mg/g.
A single spot ratio can be raised by exercise, fever, infection, menstruation, or hydration. Diagnosis of persistent albuminuria needs two or three abnormal samples over months — confirm with your clinician.
KDIGO albuminuria categories
| Category | UACR (mg/g) | Meaning |
|---|---|---|
| A1 | Under 30 | Normal to mildly increased |
| A2 | 30–300 | Moderately increased (microalbuminuria) |
| A3 | Over 300 | Severely increased (macroalbuminuria) |
Source: KDIGO 2012/2024 CKD albuminuria categories.
Common mistakes
- Using albumin and creatinine in mismatched units — both must resolve to mg/dL before dividing.
- Forgetting the ×1000, which converts mg-per-mg into mg albumin per gram creatinine.
- Treating one high spot ratio as chronic disease; transient causes like fever or exercise raise it.
- Ignoring eGFR — UACR and eGFR together define the CKD risk grid, not either one alone.
Frequently asked questions
How is UACR calculated?
Divide urine albumin by urine creatinine and multiply by 1000, with both in mg/dL. For example, 5 mg/dL albumin over 100 mg/dL creatinine is 5/100 × 1000 = 50 mg/g, which falls in the A2 range.
What is a normal UACR?
Under 30 mg/g is category A1, considered normal to mildly increased. From 30 to 300 mg/g is A2 (moderately increased), and above 300 mg/g is A3 (severely increased).
What is the difference between micro- and macroalbuminuria?
Microalbuminuria is the older name for the A2 range (30–300 mg/g) and macroalbuminuria for A3 (over 300 mg/g). KDIGO now prefers the A1–A3 labels, but the cutoffs are the same.
Can one high result be a false alarm?
Yes. Exercise, fever, infection, dehydration, and menstruation can transiently raise albumin. Persistent albuminuria requires two or three abnormal samples over about three months.
What should I do with an abnormal UACR?
Bring it to your doctor, who will repeat the test, check eGFR and blood pressure, and look for diabetes or other causes. Do not self-diagnose kidney disease from a single ratio.