Pressure Calculator & Converter
Convert between bar, psi, kPa and metres of water head — and see the pressure at the bottom of a tank.
Inputs
Tank height above the tap
Formula
- 1 bar = 14.504 psi = 100 kPa = 10.197 m of water
- Pressure from a water column: P = ρ g h
- 10 m of water ≈ 1 bar
Pressure is quoted in bar on pumps, psi on tyres and imported gear, and metres of head in plumbing. They all describe the same thing. A useful shortcut: every 10 metres of water height gives about 1 bar, which is why a tank one floor above a tap gives roughly 0.3 bar.
Step-by-step calculation
- 1
To bar
convert input unit
3 bar
- 2
Water head
bar × 10.197
30.59 m
Worked example
- 13 bar = 43.5 psi = 300 kPa = 30.6 m of water head.
- 2A tank 10 m above the tap gives 0.98 bar.
- 3That is enough for a shower, but a geyser usually wants at least 0.5 bar.
Tips
- Most taps and geysers need 0.5–1 bar; below that fit a pressure pump.
- Never exceed the pipe's rated pressure — CPVC is usually rated to 10 bar at ambient temperature.
Frequently asked questions
How many psi is 1 bar?
14.5 psi. Car tyres at 32 psi are about 2.2 bar.
How much pressure does a rooftop tank give?
About 0.1 bar per metre of height, so a tank 6 m above the tap gives 0.6 bar.
Why is my shower weak on the top floor?
The tank is too close above the outlet. Raise the tank or fit a booster pump.
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