Pressão Hidrostática
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
P = ρgh
About this calculator
The hydrostatic pressure calculator determines the pressure exerted by a fluid at rest at a given depth. It uses the formula P = ρgh, where ρ is fluid density, g is gravity, and h is fluid column height. It is essential for hydraulic engineering projects, dam design, and fluid studies.
The calculation is simple: enter fluid density (kg/m³), local gravity (default 9.81 m/s²), and depth (meters). The result is pressure in Pascals (Pa). For fresh water, ρ ≈ 1000 kg/m³; for salt water, ρ ≈ 1025 kg/m³. Hydrostatic pressure does not depend on container shape, only depth.
Use this tool to calculate pressure in tanks, reservoirs, pools, or at the bottom of the sea. It is useful for divers, civil engineers, and physics students. Hydrostatic pressure increases linearly with depth; every 10 meters of fresh water adds about 1 atm (101325 Pa).
Caution: the formula assumes incompressible fluid at rest. For gases, density varies with depth, so the formula is inaccurate. Also, total pressure at the bottom includes atmospheric pressure at the surface. The calculator provides only gauge pressure (relative), not absolute.
Frequently asked questions
What is the difference between hydrostatic pressure and absolute pressure?
Hydrostatic pressure is the pressure exerted only by the fluid column, ignoring atmospheric pressure. Absolute pressure is the sum of hydrostatic pressure and atmospheric pressure at the surface.
Can I use this calculator for gases?
No, the formula P = ρgh is valid only for incompressible fluids like liquids. For gases, density varies with depth, requiring more complex equations.
What happens if I change gravity?
Hydrostatic pressure is directly proportional to gravity. In locations with lower gravity (like the Moon), pressure would be lower for the same depth and density.
How do I convert the result to atmospheres?
1 atm = 101325 Pa. Divide the result in Pascals by 101325 to get the value in atmospheres.
Does the calculator consider atmospheric pressure?
No, it calculates only gauge pressure. To get absolute pressure, add 101325 Pa (1 atm) to the result.