Calculate urine albumin-to-creatinine ratio (ACR) from spot urine albumin and creatinine values, with results in mg/g or mg/mmol.

ACR Calculator

Use values from the same spot urine test. Do not enter blood (serum) albumin/creatinine.

Enter any 2 values to calculate the missing value

Educational use only; not medical advice. Discuss abnormal results with a clinician.

Related Calculators

ACR Formula

The urine albumin-to-creatinine ratio, or ACR, compares urine albumin with urine creatinine from the same spot urine sample. The calculator uses mg/L as the base unit for urine albumin and urine creatinine, then converts the final ACR to either mg/g or mg/mmol.

ACR₍mg / g) = (Albumin₍mg / L) / Creatinine₍mg / L)) * 1000
Albumin₍mg / L) = ACR₍mg / g) * Creatinine₍mg / L) / 1000
Creatinine₍mg / L) = Albumin₍mg / L) * 1000 / ACR₍mg / g)
ACR₍mg / mmol) = ACR₍mg / g) * 113.12 / 1000
ACR₍mg / g) = ACR₍mg / mmol) * 1000 / 113.12
  • ACR is the urine albumin-to-creatinine ratio.
  • Albumin is urine albumin from a spot urine test, entered as mg/L or mg/dL.
  • Creatinine is urine creatinine from the same spot urine test, entered as mg/dL or mmol/L.
  • 113.12 is the molecular weight factor used to convert creatinine between mmol and mg units.
  • 1000 converts the ratio from mg per mg to mg per g.

If you enter urine albumin and urine creatinine, the calculator solves for ACR. If you enter ACR and creatinine, it solves for urine albumin. If you enter ACR and albumin, it solves for urine creatinine. All values should come from the same spot urine sample, not from blood serum tests.

ACR Result Ranges

ACR category mg/g mg/mmol General interpretation
A1 Less than 30 Less than 3 Normal to mildly increased
A2 30 to 300 3 to 30 Moderately increased
A3 Greater than 300 Greater than 30 Severely increased

Unit Conversions Used for ACR

Conversion Formula
Albumin mg/dL to mg/L mg/L = mg/dL × 10
Creatinine mg/dL to mg/L mg/L = mg/dL × 10
Creatinine mmol/L to mg/L mg/L = mmol/L × 113.12
ACR mg/g to mg/mmol mg/mmol = mg/g × 113.12 ÷ 1000

Example Calculations

Example 1: Calculate ACR in mg/g

You have urine albumin of 30 mg/L and urine creatinine of 100 mg/dL.

First convert creatinine to mg/L:

100 * 10 = 1000 mg / L

Then calculate ACR:

ACR = (30 / 1000) * 1000 = 30 mg / g

Example 2: Convert ACR from mg/g to mg/mmol

You have an ACR of 30 mg/g and want the equivalent in mg/mmol.

ACR₍mg / mmol) = 30 * 113.12 / 1000 = 3.3936 mg / mmol

FAQ

What samples should I use for an ACR calculation?

Use urine albumin and urine creatinine values from the same spot urine test. Do not mix a urine albumin result with a blood creatinine result. Blood, or serum, creatinine is not the same measurement and will give an incorrect ACR.

Why does the calculator need urine creatinine?

Urine concentration changes depending on hydration and urine volume. Creatinine helps adjust the albumin result for how concentrated the urine sample is. That is why ACR is often more useful than urine albumin alone.

Is a single abnormal ACR enough to diagnose kidney disease?

No. ACR can be affected by exercise, infection, fever, menstruation, recent high blood sugar, high blood pressure, and other temporary factors. An abnormal result should be discussed with a clinician, who may repeat the test or interpret it with other kidney function results.