Pressure Calculator
From a force on an area, or from a depth of fluid.
From a force on an area, or from a depth of fluid. Pressure from a force spread over an area, or from a depth of fluid.
Standard gravity by definition. Local values run 9.78 to 9.83.
Pressure (kPa)
100
14.504 psi · 0.9869 atm
Pressure is force spread over area, which is why the area matters as much as the force. The same weight through a stiletto heel exerts far more pressure than through a flat sole, and that is the entire principle behind both snowshoes and drawing pins.
How the Pressure Calculator works
Pressure from a force spread over an area, or from a depth of fluid. Hydrostatic pressure depends on nothing but depth, density and gravity — the shape and width of the container are irrelevant, which is Pascal's result and the reason a hydraulic jack works.
Also known as: psi calculator · water pressure calculator · hydrostatic pressure calculator · pressure formula
Depth is all that matters
Hydrostatic pressure is ρgh — density, gravity, depth. Nothing about the container's shape or width appears in it.
A narrow pipe and a wide lake press equally hard at the same depth. This is Pascal's result, and it seems wrong until you notice that the water above any given point is supported by the walls as much as by the water below.
In practice
Ten metres of water is about 98 kPa, or 0.97 atmospheres, which is where the diving rule of thumb comes from. One atmosphere per ten metres is accurate to within a few percent.
Pressure is force spread over area, so the area matters as much as the force. The same person exerts far more pressure through a stiletto heel than a flat sole, which is the entire principle behind both snowshoes and drawing pins.
One standard atmosphere is 101,325 Pa exactly. That figure is a definition rather than a measurement, fixed by convention, so it is stated as exact here.
Where to go next
The Pressure question rarely arrives on its own. These are the ones that usually come with it:
- Density Calculator — Density, mass or volume, and whether it floats.
- Force Calculator — F = ma, in newtons, kilograms-force and pounds-force.
- Power Calculator — Watts, kilowatts and horsepower, with a running cost.
- Speed Distance Time Calculator — Any one of the three from the other two, in four units.
Frequently asked questions
How do I calculate pressure?
Divide force by area. 1,000 N over 100 cm² is 100 kPa, which is about one atmosphere.
How much pressure is 10 metres of water?
About 98 kPa, or 0.97 atmospheres. The diving rule of thumb — one atmosphere per ten metres — is accurate to within a few percent.
Does the width of a container change the pressure?
No. A narrow pipe and a wide lake at the same depth press equally hard. Only depth, fluid density and gravity matter.
How do I convert kPa to psi?
Divide by 6.895. So 100 kPa is 14.50 psi, and one standard atmosphere — 101.325 kPa — is 14.70 psi.
Put this calculator on your own site
Free to use, on any site, commercial or not. Paste this where you want it to appear. It is a plain iframe, so it works in WordPress, Squarespace, Wix, Webflow, Ghost and anything else that accepts HTML.
<iframe src="https://www.thecalclibrary.com/embed/pressure-calculator" width="100%" height="640" style="border:1px solid #e2e8f0;border-radius:12px" loading="lazy" title="Pressure Calculator"></iframe>
<p style="font:13px/1.5 system-ui,sans-serif;margin:6px 0 0;color:#64748b">Powered by <a href="https://www.thecalclibrary.com/pressure-calculator" style="color:#64748b">Pressure Calculator</a> from The Calc Library</p>The only condition is that the credit line below the frame stays in place. That one line is what pays for the tool being free — it is how anyone else finds it.
Related calculators
Density Calculator
Density, mass or volume, and whether it floats.
OpenForce Calculator
F = ma, in newtons, kilograms-force and pounds-force.
OpenPower Calculator
Watts, kilowatts and horsepower, with a running cost.
OpenSpeed Distance Time Calculator
Any one of the three from the other two, in four units.
Open