Quick answer Pressure in a static fluid is P = P₀ + ρ·g·h (P₀ = atmospheric pressure in Pa, ρ = density in kg/m³, g = gravity, h = depth in m), rising linearly with depth. In seawater each 10 m adds about one atmosphere (101.3 kPa), so 11,000 m reaches roughly 111 MPa. Pascal's law gives F₂ = F₁·(A₂/A₁).
Set depth and pick a fluid to compute hydrostatic pressure (gauge and absolute) and the force on a 1 m² surface.
Parameters
Environment preset
Results
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Hydrostatic pressure (absolute) (kPa)
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Gauge pressure (kPa)
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Atmospheric-pressure equivalent (atm)
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Force per 1m² (kN)
Visualization
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Depth h (m)
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Gauge pressure ρgh (kPa)
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Absolute pressure P₀+ρgh (kPa)
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Resultant wall force ½ρgH²w (kN)
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Center of pressure (m)
Drag the probe to check pressure at any depth
Theory & Key Formulas
Theory & Key Formulas
$$P = P_0 + \rho g h$$ $P_0$: atmospheric pressure (Pa), $\rho$: fluid density (kg/m³), $g$: gravitational acceleration (m/s²), $h$: depth (m)
10m of water ≈ 1 additional atmosphere (101.3 kPa). At an ocean depth of 11,000m: ≈1,100 atmospheres (111 MPa)
Pascal's law
$\dfrac{F_2}{A_2} = \dfrac{F_1}{A_1}$ (pressure is transmitted equally in all directions)
Hydraulic cylinder: $F_2 = F_1 \times \dfrac{A_2}{A_1}$ (force amplified by the area ratio)
Why does pressure increase by 1 atm every 10 m depth?
Water density 1000 kg/m³ × gravity 9.8 m/s² × 10 m ≈ 98 kPa ≈ 1 atm. The Mariana Trench at ~11 km has about 1100 atm.
Why do ears hurt when diving?
Increasing water pressure pushes on the eardrum. Equalizing pressure by pushing air through the Eustachian tubes resolves this.
Is blood pressure related to hydrostatic pressure?
Yes. Blood vessels above the heart have lower pressure; vessels below have higher. Standing up quickly can cause dizziness due to reduced head pressure.
What is the pressure at the Mariana Trench?
About 108 MPa (~1100 atm) at 11,034 m depth. ROVs require specialized pressure-resistant designs.
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I can see the simulation updating, but what exactly is being calculated here?
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Great question! The simulator solves the governing equations in real time as you move the sliders. Each parameter you control directly affects the physical outcome you see in the graph. The key is to build an intuitive feel for how each variable influences the result — that's how engineers develop physical judgment.
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So when I increase this parameter, the curve shifts significantly. Is that a linear relationship?
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It depends on the model. Some relationships are linear, but many engineering phenomena are nonlinear. Try moving the sliders to extreme values and see if the output changes proportionally — if the graph shape changes, that's a sign of nonlinearity. This hands-on exploration is exactly what simulations are best for.
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Where is this kind of analysis actually used in practice?
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Constantly! Engineers run these calculations during the design phase to quickly screen parameters before investing in expensive physical tests or detailed finite element simulations. Getting comfortable with these simplified models is a real engineering skill.
Select fluid type (water, seawater, or oil) or enter custom density in kg/m³ using the dropdown menu
Input submersion depth in meters into the depth field (sH/sHNum)
Specify the submerged surface area in m² to compute total hydrostatic force
Click Calculate to obtain gauge pressure (relative to atmospheric), absolute pressure (including 101.325 kPa ambient), and resultant force in kN
Review pressure distribution diagrams showing pressure increase linearly with depth
Worked Example
A dam gate submerged to 8.5 m depth in freshwater (ρ=1000 kg/m³) with exposed area 12 m²: gauge pressure = 1000 × 9.81 × 8.5 = 83.35 kPa; absolute pressure = 184.68 kPa; hydrostatic force = 83.35 × 12 = 1000.2 kN acting perpendicular to the gate surface. For seawater (ρ=1025 kg/m³) at 15 m depth on a porthole (0.5 m²): gauge pressure reaches 150.8 kPa, absolute pressure 252.1 kPa, force = 75.4 kN.
Practical Notes
Centroid method: hydrostatic force acts at 2/3 depth for triangular pressure distribution on vertical submerged planes; use simulator depth input to verify center-of-pressure calculations for structural analysis
Seawater density varies 1025–1030 kg/m³ by salinity; submarine hull designs typically use 1027 kg/m³ for worst-case scenarios
Gauge pressure is engineering-critical for pipeline, vessel, and lock gate design; absolute pressure drives material selection and corrosion risk assessment
Temperature effects: freshwater density decreases ~0.2% per 10°C rise above 4°C, affecting pressure calculations for heated reservoirs