Fluid Calculators: Density, Pressure, Buoyancy and Flow

These fluid calculators solve the core problems of fluid mechanics, from static liquids to flowing streams. Use the Density calculator to find mass per unit volume, check Specific Gravity to compare a substance with water, and compute Buoyant Force to see why objects float or sink.For pressure-related tasks, the Pressure and Hydrostatic Pressure calculators handle force per area and depth-dependent pressure in liquids. Bernoulli's Equation calculator analyzes energy conservation in moving fluids, useful for pipes and flow problems. These tools are built for physics students, engineers, and anyone working with liquids or gases in homework, labs, or practical projects.

Hydrostatic Pressure

Calculate the hydrostatic pressure at any depth in water or another fluid. Enter depth, fluid density and gravity to get gauge and absolute pressure in kPa, bar, psi, atm and mmHg.

Specific Gravity

Enter a density (or mass and volume) and instantly get specific gravity relative to water, seawater, air or a custom reference, plus the density converted into common units.

Froude Number

Enter the flow speed, flow depth and gravity to compute the Froude number and find out whether your open-channel flow is subcritical, critical or supercritical, with critical-speed details.

Laplace Pressure

Calculate the Laplace pressure (excess pressure) inside a droplet, soap bubble, or cylindrical liquid surface. Enter the surface tension and radius of curvature to get the pressure difference in Pa, kPa, psi, mmHg and more.

Density

Calculate density from mass and volume, or solve for mass or volume when density is known. Supports kg, g, lb, L, m³, gal and more, with instant unit conversion.

Buoyant Force

Calculate the buoyant force on an object from fluid density, displaced volume, and gravity, following Archimedes' principle. Optionally enter the object's weight to get its apparent weight and see whether it floats or sinks.

Pressure

Calculate pressure from force and area (or solve for force or area) using P = F / A. Enter any two known values, pick your units, and get the result in Pa, kPa, bar, psi and more.

Bernoulli's Equation

Solve Bernoulli's equation for the missing pressure, velocity or elevation at a second point along a streamline. Enter the full conditions at point 1, leave one point-2 field blank, and the calculator finds the unknown.