Urine Specific Gravity Calculator

Urine specific gravity (USG) measures how concentrated your urine is compared to pure water. Pure water has a specific gravity of exactly 1.000. Urine is always denser than water because it contains dissolved solutes: salts, urea, creatinine, and other waste products.

The measurement:

USG = Urine Density / Water Density

Clinically, this is measured with a urinometer, a refractometer, or a dipstick test. The value reflects how hard your kidneys are working to concentrate or dilute urine in response to your hydration status.

Two different questions, two different lines. A clinical laboratory asks whether the kidneys are working, and MedlinePlus, the US National Library of Medicine’s reference, gives the normal range for a random sample as 1.005 to 1.030. Sports medicine asks whether you are drinking enough, and the American College of Sports Medicine counts 1.020 or more as underhydrated. So a 1.025 is a normal lab result and a poorly hydrated athlete at the same time.

How this page reads a number:

Below 1.005: Very dilute, below the lab range. Usually just a lot of water. Persistently this low without heavy drinking can point to diabetes insipidus or a kidney that has lost its ability to concentrate.

1.005 to 1.019: Normal, and well hydrated by the sports-medicine line too.

1.020 to 1.030: Still inside the lab’s normal range, but concentrated. Most often mild dehydration, and the first-morning sample usually sits here. Drink more through the day.

Above 1.030: Very concentrated. Significant dehydration, a high-protein diet, sugar or contrast dye in the urine, or kidney stress. Sustained values above 1.030 warrant medical evaluation.

One important nuance: first morning urine is naturally more concentrated than samples taken throughout the day, and some medications (diuretics, contrast agents) can artificially alter USG. Interpret readings in context. This calculator is for educational reference. A healthcare provider interprets a reading alongside everything else they know.