🔧 Head Pressure Calculator
Calculate the relationship between pressure and hydraulic head using the fundamental fluid mechanics formula P = ρgh. Convert between pressure and head, or calculate the required head for a given pressure. Supports multiple units and includes common fluid density references.
What Is Head Pressure?
Head pressure (or hydraulic head) is the height of a liquid column that corresponds to a specific pressure. It is a fundamental concept in fluid mechanics, hydraulics, and pump engineering. The relationship between pressure and head is given by:
P = ρ · g · h
where P = pressure (Pa), ρ = fluid density (kg/m³), g = gravitational acceleration (m/s²), h = head (m)
Head pressure has several important applications:
- Pump engineering: Calculating the head required to pump fluids to a certain height.
- Hydraulic systems: Determining the pressure generated by a fluid column.
- Water supply: Calculating water pressure at different elevations.
- Diving: Understanding the pressure increase with depth.
How to Convert Between Pressure and Head
The two key formulas are:
From Pressure to Head: h = P / (ρ · g)
From Head to Pressure: P = ρ · g · h
For example, to convert 10 meters of water head to pressure:
P = 1000 × 9.81 × 10
P = 98,100 Pa ≈ 98.1 kPa ≈ 1 atm
To convert 1 atm (101,325 Pa) to head of water:
h = 101325 / (1000 × 9.81)
h ≈ 10.33 m of water
Why Use This Converter?
- Two-way conversion: Convert from pressure to head or head to pressure.
- Multiple units: Supports various pressure, head, and density units.
- Step-by-step breakdown: See exactly how the conversion is calculated.
- Free & private: No registration, no data storage — all calculations are done in your browser.
❓ Head Pressure Calculator FAQ
What is head pressure?
Head pressure (or hydraulic head) is the height of a liquid column that corresponds to a specific pressure. It is commonly used in pump engineering and fluid mechanics.
What is the formula for head pressure?
The formula is P = ρgh, where P is pressure, ρ is fluid density, g is gravity, and h is head. To find head from pressure: h = P / (ρg).
How much pressure is 10 meters of water?
10 meters of water creates approximately 98.1 kPa (0.981 bar, 14.2 PSI), which is nearly 1 atmosphere.
How many meters of head is 1 bar?
1 bar (100 kPa) corresponds to approximately 10.2 meters of water head.
What is the density of water?
Freshwater has a density of approximately 1000 kg/m³ (1 g/cm³) at 4°C.
What is the standard value for gravity?
The standard value for gravity is 9.80665 m/s². For most calculations, 9.81 m/s² is sufficient.
How is head pressure used in pump engineering?
In pump engineering, head is used to specify the height a pump can lift a fluid. Total head includes static head, friction losses, and velocity head.
How accurate is this calculator?
This calculator uses the exact formulas P = ρgh and h = P/(ρg). Accuracy depends on the precision of the input values. You can adjust the decimal precision in the output.
Is this calculator free?
Yes, this calculator is completely free to use. No registration or personal data storage is required.
What units does this calculator support?
Pressure: Pa, kPa, bar, PSI, atm, kgf/cm². Head: m, cm, mm, ft, in. Density: kg/m³, g/cm³, lb/ft³.