Level Measurement · Glossary

What is Hydrostatic Level Measurement?

level from pressureLevel Measurement

Hydrostatic level measurement finds liquid level from the pressure at the bottom of a tank and the liquid density.

Hydrostatic Level Measurement Explained

The pressure under a liquid column depends only on its height and density. A pressure transmitter at the bottom of an open tank, or a submersible probe, therefore measures level.

Accuracy depends on knowing the density. If density changes with temperature or product, the level reading changes too, unless density is measured or compensated.

Hydrostatic Level Measurement Formula

h = p ÷ (ρ × g)

h	level above the tap (m)
p	gauge pressure at the tap (Pa)
ρ	liquid density (kg/m³)
g	9.80665 m/s²

Example: 24.5 kPa on water at 1000 kg/m³: h = 24,500 ÷ 9806.65 ≈ 2.50 m.

Calculators for Hydrostatic Level Measurement

CalculatorPressure to Level CalculatorFree online calculator with formula and worked example.CalculatorHydrostatic Tank Gauging CalculatorFree online calculator with formula and worked example.CalculatorHydrostatic Pressure CalculatorFree online calculator with formula and worked example.

Free Downloads

Free downloadLevel Measurement Formulas Cheat SheetFree printable PDF cheat sheet.

Frequently Asked Questions

What is Hydrostatic Level Measurement?

Hydrostatic level measurement finds liquid level from the pressure at the bottom of a tank and the liquid density.

Can a gauge transmitter measure level in a closed tank?

Only if the tank is at atmospheric pressure. A pressurised tank needs a DP transmitter so the gas pressure above the liquid is subtracted.

Why does the level reading change with temperature?

Liquid density falls as it warms, so the same mass gives less pressure per metre. The transmitter cannot tell this from a level change.

Learn more on the blog

Hydrostatic level measurement

A practical guide on instrumentationblog.in with more detail on hydrostatic level measurement and how it is applied on real plants.

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More Level Measurement Terms

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