What Is the Density of Water?

Close up of water against a blue background.

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by Anne Marie Helmenstine, Ph.D.
Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
Updated May 04, 2019

The density of water is the weight of the water per its unit volume, which depends on the temperature of the water. The usual value used in calculations is 1 gram per milliliter (1 g/ml) or 1 gram per cubic centimeter (1 g/cm3). While you can round the density to 1 gram per milliliter, there are more precise values for you to use.

The density of pure water actually is somewhat ​less than 1 g/cm3. A standard table lists the values for the density of liquid water. Note that water can be supercooled and remain a liquid well below its normal freezing point. The maximum density of water occurs around 4 degrees Celsius. Ice is less dense than liquid water, so it floats.

Temp (°C)  Density (kg/m3) 

+100  958.4
+80   971.8
+60   983.2
+40   992.2
+30   995.6502
+25   997.0479
+22   997.7735
+20   998.2071
+15   999.1026
+10   999.7026
+4    999.9720
0     999.8395
−10   998.117
−20   993.547
−30   983.854