Water Pressure Calculator
Convert water pressure between bar, psi, kPa, MPa and atmospheres — and see the equivalent head of water in metres and feet.
Pressure is quoted in bar, psi, kPa and atmospheres — often on the same job. This calculator converts between all five, and shows the head of water the pressure supports.
Enter the pressure; every unit follows.
Your results
Enter your measurements and press Calculate.
Quantities are rounded up to whole tiles, planks, boxes or bags, after the wastage allowance. Cost appears only when you enter a price.
Formula
All lengths are converted to a single unit before the calculation: 1 ft = 0.3048 m, 1 in = 25.4 mm, 1 ft² = 0.09290304 m², 1 yd² = 9 ft². Material quantities are rounded up — you cannot buy part of a tile, plank or bag.
How to use this calculator
- Enter the pressure and its unit.
- Read the pressure in bar, psi, kPa, MPa and atmospheres.
- Read the head of water in metres and feet.
- Use the Copy results button to copy the answer.
Worked example
| Pressure | 3 bar |
|---|---|
| psi | 3 ÷ 0.0689476 = 43.51 psi |
| kPa | 3 × 100 = 300 kPa |
| MPa | 3 ÷ 10 = 0.3 MPa |
| Head | 3 × 10.19716 = 30.59 m (100.37 ft) |
Check it by hand: every step above uses the formula in the box. If your numbers match the example inputs but the calculator gives a different answer, please report it via the contact page.
Frequently asked questions
What is normal household water pressure?
Typically 2–4 bar (29–58 psi). Below 1 bar, showers go weak; above 5 bar, fittings and appliances can be stressed. Check yours with a gauge on an outside tap.
What is head of water?
The height of a column of water that the pressure supports — 1 bar supports 10.19716 m. A tank 10 m above a tap gives about 1 bar at the tap. This calculator shows the head for any pressure.
How many psi are in a bar?
14.5038 psi. So 3 bar is 43.51 psi. This calculator converts between bar, psi, kPa, MPa and atmospheres.
Is this a substitute for plumbing design?
No. This is a conversion for planning. Pressure, pipe sizing and code compliance depend on local regulations and real installation conditions — see the safety notice.
Related calculators
Estimates only. Results are for planning. Measure twice, confirm box coverage and tile sizes on the packaging you buy, and follow the manufacturer's instructions. See the disclaimer.