How to use the urine specific gravity lookup
Enter a refractometer reading and the page finds which of the four Casa et al. (2000) categories it falls in: under 1.010, 1.010 to 1.020, above 1.020 up to 1.030, and over 1.030. The categories run with no gaps (the source writes the third one as 1.021 to 1.030), and the reading you enter is classified as is, before any rounding for display.
Basis and limits
These categories were confirmed through a secondary source. The American College of Sports Medicine used 1.020 or below as normal hydration for weight certification, and measuring the first morning sample is the thrust of the 2017 National Athletic Trainers' Association position statement. In a study of Division I college athletes, however, urine specific gravity categories did not agree with existing hydration classifications and the authors concluded they may need revising (as of October 2026).
Measurement needs a refractometer. This page does not use urine color, does not score symptoms, and does not calculate how much fluid to drink. The category is a reference value, not a diagnosis of dehydration, and no category guarantees that hydration is adequate. Dizziness, altered awareness, or passing almost no urine need care straight away, whatever the reading.
Frequently Asked Questions
This page does not use a color scale. The reading has to come from a refractometer, and the position statement points to the first morning sample.
The source writes the categories to three decimal places as 1.010 to 1.020 and 1.021 to 1.030. To leave no gap, this page treats 1.020 or below as minimal dehydration and anything above 1.020 up to 1.030 as significant dehydration. For example, 1.0205 is significant dehydration, and the boundary values 1.010, 1.020 and 1.030 each fall in exactly one category.
No. In the Division I athlete study these categories did not agree with existing hydration classifications. The category is a reference value and diagnosis comes only from clinical assessment.