Kidney calculator
Urine albumin-to-creatinine ratio calculator
The urine albumin-to-creatinine ratio (UACR or ACR) checks a urine sample for albumin, a protein that leaks through damaged kidney filters. Work out your ratio from the two numbers on your lab report, or enter the ratio itself, and see which KDIGO category, A1 to A3, it falls in.
Your urine test
Use numbers from the same urine sample. Nothing you enter leaves this page.
What you will see
Your ratio in mg/g and mg/mmol, the working, and your KDIGO albuminuria category.
Educational only, not medical advice. One urine result cannot diagnose kidney disease.
Source
KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease (albuminuria categories and unit conversion). NIDDK (NIH) for what the test is and who should be checked.
Validated in
Adults. The categories are the international guideline's grading of urine albumin, used together with eGFR to stage chronic kidney disease.
Limits
A ratio from one sample. KDIGO asks for a raised result to be confirmed and to last more than 3 months before it counts as kidney disease. Not for children (KDIGO gives separate advice for them), and not a substitute for your lab's own report or your clinician's reading.
How the ratio is worked out
UACR divides the amount of albumin in a urine sample by the amount of creatinine in the same sample. NIDDK explains that providers use it to estimate how much albumin would pass into your urine over 24 hours (NIDDK). Dividing by creatinine corrects for how dilute or concentrated the sample is.
- mg/g (US): albumin in mg/L divided by creatinine in g/L. Creatinine in mg/dL divided by 100 gives g/L. For example, albumin of 45 mg/L and creatinine of 150 mg/dL (1.5 g/L) give 45 ÷ 1.5 = 30 mg/g.
- mg/mmol (most other countries): albumin in mg/L divided by creatinine in mmol/L. For example, 30 mg/L ÷ 10 mmol/L = 3 mg/mmol.
KDIGO gives 0.113 as the factor from mg/g to mg/mmol, and 88.4 to turn creatinine in mg/dL into µmol/L (KDIGO 2024). If your albumin is in mg/dL, we multiply by 10 to get mg/L. The guideline advises reporting ACR to one decimal place (KDIGO 2024), so we do the same.
The A1 to A3 categories
KDIGO grades albuminuria in three categories (KDIGO 2024):
| Category | ACR (mg/g) | ACR (mg/mmol) | Description |
|---|---|---|---|
| A1 | Under 30 | Under 3 | Normal to mildly increased |
| A2 | 30 to 300 | 3 to 30 | Moderately increased |
| A3 | Over 300 | Over 30 | Severely increased |
The guideline calls the mg/g and mg/mmol lines approximate equivalents (KDIGO 2024), so a value right at a line can fall in a different category in the other unit. We place your result using the unit it was worked out in. NIDDK puts its line slightly differently: 30 mg/g or less is normal, and more than 30 mg/g may be a sign of kidney disease (NIDDK).
One raised result is not a diagnosis
Chronic kidney disease means a problem with kidney structure or function that lasts more than 3 months, and an ACR of 30 mg/g (3 mg/mmol) or more is one of the markers (KDIGO 2024). KDIGO advises confirming a raised ACR from a random urine sample with a first morning sample (KDIGO 2024), and NIDDK notes your provider may repeat the test one or two more times (NIDDK).
Some things can make a single result read higher than usual. KDIGO lists exercise, menstruation, blood in the urine and a symptomatic urinary infection. Because the ratio uses creatinine, it also shifts with how much creatinine you make: women and people with low body weight tend to have higher ratios, and men and people with high body weight lower ones (KDIGO 2024).
Read it together with eGFR
The urine test looks for leaking protein; eGFR, from a blood test, measures how well the kidneys filter. Someone can have a normal eGFR and a raised ACR, and KDIGO combines the two into one chart of the outlook (KDIGO 2024). Work out your eGFR with the eGFR calculator, and see how the G and A categories combine in kidney disease stages, explained. Not tested yet? The kidney disease risk score (SCORED) is a self-check for who should be.
Who should have their urine checked
Early kidney disease usually has no symptoms, so testing is the only way to know. NIDDK advises getting checked if you have diabetes, high blood pressure, heart disease or a family history of kidney failure, and every year if you have diabetes (NIDDK). CDC estimates that about 14% of US adults have chronic kidney disease and that about 9 in 10 of them do not know it (CDC).
Sources
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4S):S117-S314. doi.org/10.1016/j.kint.2023.10.018
- National Institute of Diabetes and Digestive and Kidney Diseases (NIH). Chronic Kidney Disease Tests and Diagnosis. www.niddk.nih.gov/health-information/kidney-disease/chronic-kidney-disease-ckd/tests-diagnosis
- Centers for Disease Control and Prevention. Chronic Kidney Disease in the United States. www.cdc.gov/kidney-disease/php/data-research/index.html
Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-11-01. Spotted an error? See About.