---
title: "Pressure and density calculator — free, runs in your browser"
description: "Pressure from force and area, fluid pressure with depth, density and buoyancy. Free, no sign-up, and nothing you enter leaves your browser."
url: https://atoneplace.net/tools/pressure-density-calculator/
site: "At One Place"
---

# Pressure and density calculator

Pressure from force and area, fluid pressure with depth, density and buoyancy.

## How it works

Calculates pressure from force and area, hydrostatic pressure at depth, density from mass and volume, and whether an object floats.

Pressure is force divided by area, which is why a drawing pin works and a snowshoe works — the same force spread over a different area. A person weighing 700 N standing on two feet exerts about 20 kPa; the same person on a stiletto heel exerts more than a tonne per square centimetre, which is why heels damage floors.

Fluid pressure depends only on depth, density and gravity, not on the shape or volume of the container. A tall thin tube of water exerts the same pressure at its base as an ocean at the same depth, which is the hydrostatic paradox and is genuinely counterintuitive.

Water adds about one atmosphere for every ten metres of depth. Floating is decided entirely by density relative to the fluid: less dense floats, more dense sinks, and shape only matters because it changes average density by trapping air.

> This tool runs entirely in your browser. Nothing you enter is sent to a server, logged or stored, and the page keeps working with the network disconnected.

## Common questions

### Why does pressure increase with depth?

Because the weight of the fluid above accumulates. Roughly one extra atmosphere per ten metres of water.

### Does a wider container mean more pressure at the bottom?

No. Fluid pressure depends only on depth, density and gravity — not on the container shape or the total volume.

### Why do steel ships float?

Because average density, not material density, decides it. A hull full of air is less dense than water overall.

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## Sources

- Calculated on this page — At One Place (/about/)