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Water pressure calculator

Convert between water head and pressure, and between kPa, bar, metres and psi — for tank heights, mains pressure and pump duties.

Head or pressure
Enter one and read the others.
Pressure
294 kPa
Equivalent to 30.0 m of head, 2.94 bar or 42.7 psi.
Head (metres)30.0 m
Pressure (kPa)294 kPa
Pressure (bar)2.94 bar
Pressure (psi)42.7 psi

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How it works

1

Head becomes pressure

A column of water creates pressure at its base. Every metre of height adds about 9.81 kPa, so a 30 m head is roughly 294 kPa.

2

One relationship, many units

Head, kPa, bar and psi all describe the same thing. Knowing one lets you convert to any of the others.

3

Use it on the job

Whether you’re checking mains pressure, tank height or a pump duty, converting between head and pressure makes the numbers line up.

Frequently asked questions

How does height relate to water pressure?

Each metre of vertical water height (head) produces about 9.81 kPa of static pressure. So a header tank 20 m above an outlet gives roughly 196 kPa before any flow, and a 30 m head gives about 294 kPa. Pressure drops once water flows, due to friction in the pipes.

What are the common pressure units?

Australia uses kilopascals (kPa) for water pressure. 100 kPa equals 1 bar and about 14.5 psi, and corresponds to roughly 10.2 m of head. This tool converts between all of them.

What water pressure is normal?

Mains water pressure commonly sits around 200–500 kPa. Many fixtures and appliances have a maximum operating pressure (often 500 kPa), so a pressure-limiting valve is used where mains pressure is higher to protect the plumbing.

Does this account for flow and friction?

No — it gives static pressure from head only. Once water flows, friction in pipes and fittings reduces the pressure available at the outlet. Sizing for real installations needs a pressure-loss calculation to AS/NZS 3500.

This calculator gives static pressure from head and unit conversions only. It doesn’t account for friction losses under flow. Plumbing design and pressure requirements must follow AS/NZS 3500 and be carried out by a licensed plumber.

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traqR keeps plumbing job details, test results and certificates on the site record. Try it free for 14 days.

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