---
title: "Body water — what it does and the numbers"
description: "About 60% of an adult male by mass, 55% of an adult female. What it does, where it is, the figures people look up, and the widely repeated claims that turn out to be"
url: https://atoneplace.net/body/body-water/
site: "At One Place"
---

# Body water

**Body water: About 60% of an adult male by mass, 55% of an adult female.**

Water is the medium for essentially every biochemical process, transports nutrients and waste, cushions joints and organs, and carries heat to the skin for cooling.

## The numbers

- **Adult male:** about 60%
- **Adult female:** about 55%
- **Newborn:** about 75%
- **Brain and heart:** about 73%
- **Bone:** about 31%

## Worth knowing

The male–female difference is not about hydration but body composition: fat tissue holds much less water than muscle, and women carry a higher proportion of body fat on average. The figure falls with age, from about 75% at birth to nearer 50% in later life.

> Structural reference only — this is not medical advice, and individual variation in every figure here is substantial. Anything concerning your own health belongs with a clinician rather than a reference page.

## Common questions

### What does the body water do?

Water is the medium for essentially every biochemical process, transports nutrients and waste, cushions joints and organs, and carries heat to the skin for cooling..

### Body water — key numbers

Adult male: about 60%. Adult female: about 55%. Newborn: about 75%. Brain and heart: about 73%. Bone: about 31%.

## Related pages

- [Cells in the body](https://atoneplace.net/body/cells/)
- [Heart](https://atoneplace.net/body/heart/)
- [Brain](https://atoneplace.net/body/brain/)
- [Bones](https://atoneplace.net/body/bones/)
- [Blood types](https://atoneplace.net/body/blood-types/)
- [Teeth](https://atoneplace.net/body/teeth/)
- [Blood](https://atoneplace.net/body/blood/)

## Sources

- Typical range compiled from manufacturer specifications — At One Place (/about/)