Hydrostatic Pressure Force

About this calculator

Hydrostatic force on a flat submerged surface is F = ρ × g × h̄ × A, where ρ is fluid density, g is gravitational acceleration, h̄ is the depth of the surface's centroid below the fluid surface, and A is the surface area — it works because pressure increases linearly with depth, so the centroid depth gives the correct average pressure across the whole surface.

Civil and structural engineers use this exact calculation to size dam walls, tank sides, retaining walls and submerged gates, since getting the total force wrong on something holding back water has serious consequences — a swimming pool wall and a small dam are sized using the identical physics, just at very different scales.