Worked examples
| Temperature | Fresh water density | Note |
|---|---|---|
| 0 C | 999.84 kg/m3 | just above freezing |
| 4 C | 999.97 kg/m3 | maximum density |
| 20 C | 998.21 kg/m3 | room temperature |
| 100 C | 958.4 kg/m3 | boiling point |
Common questions
At what temperature is water most dense?
Fresh water reaches its maximum density of about 999.97 kg/m3 at 4 C, which is why ice floats and lakes freeze from the top down.
Why is seawater denser than fresh water?
Dissolved salts add mass without adding much volume, so seawater at 35 ppt is roughly 1,025 kg/m3 versus about 1,000 for fresh water.