Use the free Water Pressure from Height Calculator below: your data never leaves your browser — all work happens on your device, and nothing is uploaded to any server.
Water pressure from a tank does not come from a pump or a mystery setting. It comes from height. The higher the water sits above the outlet, the harder it pushes down, and that push is the pressure you feel at the tap. The Water Pressure from Height Calculator turns height into pressure in seconds. You enter how high the water surface sits above the outlet, in feet, and it gives the pressure in PSI, bar, and kilopascals, using the simple physics of a column of water.
Using the tool is as simple as measuring one vertical distance. Stand at the outlet, such as a tap or a shower head, and measure straight up to the surface of the water in the tank, not along the pipe route. Bends, horizontal runs, and pipe length do not change this static pressure, only the vertical height does. Enter that height, and the tool multiplies it by 0.4335 to get PSI. That figure, about 0.43 PSI per foot, is one of the most useful numbers in home water systems, and it is worth remembering.
The physics is pleasingly simple. Water weighs about 62.4 pounds per cubic foot, and pressure is weight spread over area. A column of water one foot tall pushes down with 0.4335 pounds per square inch. Ten feet gives about 4.3 PSI, thirty feet gives about 13 PSI, and a hundred feet gives about 43 PSI. The tool also converts into bar, by multiplying PSI by 0.0689, and into kilopascals, by multiplying by 6.895. Those conversions matter because tanks, gauges, and appliance manuals use different units in different countries.
Those numbers explain a lot of everyday experience. A header tank in a loft, perhaps 15 feet above a ground-floor tap, gives only about 6.5 PSI, which is why some gravity-fed showers feel gentle. A tank on a hill 100 feet above a house gives a strong 43 PSI without any pump at all. They also explain why the top floor of a tall building has weaker pressure than the ground floor on the same supply: every floor of height costs pressure. If a shower is weak upstairs but fine downstairs, height is the first suspect, not the shower itself.
This tool is an educational estimator only, not professional plumbing advice. It gives static pressure, the pressure when no water is flowing. When water flows, friction in pipes reduces the pressure at the outlet, sometimes a lot on a long or narrow run. Results are estimates for planning, not guarantees of flow. Check your local plumbing codes, and consult a licensed plumber before any real installation, tank relocation, or change to a pressurised system. Never work on a tank or a pressurised line without knowing how to isolate it.
To use the result well, compare it with what your fixtures need. Many showers and appliances work best between about 20 and 60 PSI, and some need a minimum pressure to open a valve at all. If the height alone gives less than the minimum, you may need a pump, a higher tank, or a different fixture, and that choice is worth a professional opinion. If the pressure is very high, above about 80 PSI, a pressure-reducing valve may be needed to protect pipes and appliances. Height gives you the starting number for all of those decisions.
The Water Pressure from Height Calculator is free, it runs entirely in your browser, and nothing you enter leaves your device. Use it to check a tank position, understand a weak shower, or plan a gravity-fed system before you spend money. Measure the vertical height honestly, read the pressure in the units your gauge uses, and remember that flowing pressure will be lower. Height is free pressure, and this tool tells you exactly how much of it you have.
Related tools
- Calculadora de Presión de Agua por Altura (Spanish version)
- Pipe Pressure Drop Calculator
- Water Heater Size Calculator